Hello folks.
Well, who among you can explain me technically about the diference between Xperia's Official ROMs version "a" and "i"? Are there a software or hardware direfence between them?
appreciate your future help!
Sony generally speaking will name devices with an "a" at the end for US market and "i" for international market. (e.g. I used to have a W200i. In US, this same phone was the W200a). There is probably not a huge difference in software versions, but it'd most likely be safest to stick to ones for your specific device.
EDIT: (For the record, the W200 was not an Android phone, this was a few years back before Sony (Sony Ericsson at the time) really adopted Android, and it was a budget phone anyway. However I do believe I installed a US version of the firmware on it without issues - but it Android is a far more advanced OS than what that phone had obviously)
SifJar said:
Sony generally speaking will name devices with an "a" at the end for US market and "i" for international market. (e.g. I used to have a W200i. In US, this same phone was the W200a). There is probably not a huge difference in software versions, but it'd most likely be safest to stick to ones for your specific device.
EDIT: (For the record, the W200 was not an Android phone, this was a few years back before Sony (Sony Ericsson at the time) really adopted Android, and it was a budget phone anyway. However I do believe I installed a US version of the firmware on it without issues - but it Android is a far more advanced OS than what that phone had obviously)
Click to expand...
Click to collapse
Tx bro 4 answer, but in fact i need information about Xperia's Official Roms, coz i read there are problems with frecuency band ii is true?
I need information pls!!!
SteBanVe said:
Tx bro 4 answer, but in fact i need information about Xperia's Official Roms, coz i read there are problems with frecuency band ii is true?
I need information pls!!!
Click to expand...
Click to collapse
There could be issues, different countries use different frequencies of radio waves for mobile networks. Although I'd have thought pretty much every Android phone would be at least tri-band if not quad-band, meaning they support all the commonly used frequencies. So in theory, for example, a US and a European phone should both be tri/quad band and therefore be capable of using the same 3/4 frequencies, so it shouldn't make a difference. However, I have no experience, I'm just guessing here. Probably not best to take this as even close to fact
Hmmm, ok i have a question
For example, i'm from one of America's Country, where 3G connection works good, so i buy a Xperia Play version "A" (R800a) , coz "a" version works with 3G connection, then i decided flash it with "i" version (R800i)...
The question is: With "I" version (R800i), does 3G connection work like a "a" version R800a ?
In fact, will 3G connection also work good with R800i ("i" version)?
In fact, If i flash with R800i ROM in my R800a phone, do i lost 3G connection? and if i'm from europe, if i flash my R800i phone with a R800a ROM, do i win 3G connection???
i do this questions because a lot of people said that isn't there difference, and it is a hardware problem and no software problem? is it true? Helpppppppp
Thanks for ur future answer!!!
Can any moderator move this thread to Sony Mobile Area?
I need more asnwres and expirience about it
TX
Related
Anyone know which model xperia active st17i or st17a will work with 3g tmobile usa?Thanks
Fxxxx said:
Anyone know which model xperia active st17i or st17a will work with 3g tmobile usa?Thanks
Click to expand...
Click to collapse
ST17a, even though it is not sure if it will completely work.
2011 Xperia phones are mainly for Europe and Asian market.
was there any resolve on this, I am thinking about buying an active as well, and would like to use 3g on t-mobile.
any help is appreciated, thanks!
st17a + T-mobile = edge only...
cturner06 said:
was there any resolve on this, I am thinking about buying an active as well, and would like to use 3g on t-mobile.
any help is appreciated, thanks!
Click to expand...
Click to collapse
unfortunately, the st17a will not recieve T-Mobile
3g. at least, that's what i'm experiencing thus far.
which is kinda disappointing. all things considered, i
think the xperia active is a great phone. it's durable,
compact and very water resistant. i like that i can leave
it in my back pocket and go about my day. not something
i could get away with when i had my garminfone.
it could use more horsepower all around though. i hope it
did well enough in the market to warrant an upgraded
successor. i'd like to see it come back with a faster cpu,
more ram, definitely a better camera(8 megapixels or
more, though 5 isn't bad), diver-grade water resistance
and of course, support for 4g speeds accross all major us
carriers.
i'm a little puzzled as to why it was stifled in the first place.
but after witnessing what happend to the galaxy s3 when
it hit t-mobile, i'm not so surprised.
here's what's funny to me though: in my frustrations i found
a taredown of the xperia mini pro on ifixit.com. scroll down a bit
to where it shows an exposed shot of the x10's chipset and it lists
the qualcomm rtr6285, which i think is basically the phone's radio
transciever. now the 'mainboard' of my T-Mobile garminfone also
contains the qualcomm rtr6285. well, since the xperia active is
supposedly an ip-67 certified version of the xperia mini pro, then
it must also contain a similar chipset. at least in my mind, it should
be rockin' the same radio chip. this is my first post, so i can't include
external links. just google: "sony ericsson xperia x10 mini pro e10i
taredown" and the link should be one of the first results.
the garminfone works just fine on t-mobile's 3g network.
therefore, the xperia active should also function since it
theoretically uses the same radio. i could be wrong, since
i've yet to open my st17a and verify that it does contain
the same qualcomm radio chip... i emailed sony about
this and they basically told me that they won't help.
so, here i am holding out for the next gen xperia active...
there really should be more options for this type of smartphone.
however powerful and impressive alot of the newer devices are,
they're still not rugged enough to resist water or an eight foot
drop to the ground.
yep it does not work
Bought the phone about a month ago, I'm very satisfied with it. Only drawback is that it doesn't work with T-Mobile's 3G network in the United States, but it connects to 2G/Edge just fine. I like the small size, so many smartphones are big and take up a lot of pocket space, this one fits easily into my pocket and doesn't get in the way at all.
Click to expand...
Click to collapse
source: amazon reviews for st17a
it should work with at&t networks...straight talk...net10...etc
sk17a use 850/1900 3g band
tmobile: 1700/2100
at&t: 850/1900
the s3 is the same build in europe and america, but because samsung couldnt get lte working with their processor in time, they used a different one in the US. most of you know this. europe is finally starting to get 4g right? (took you long enough), do you think well see the exact same model released (with just maybe different radio bands) in both?
as an american phone user, you either buy the international phone and and get development, or you buy the US one and get monster LTE 50mbps.. i want both. its not just our side that would benefit tho. development wouldnt be split between regions, it could all be shared and collaborated. well im asking if you think itll happen, not convincing you why its a good idea lol..
so do you guys think itll happen?
Most probably yes, samsung was not ready with lte based exynos soc when s3 was launched, hence the variation. If you see note 2 the spec is almost same everywhere
《posted from my beast》
Will the different LTE frequencies still not cause an issue then?
With each carrier having there own model?
Mike Blitz said:
Will the different LTE frequencies still not cause an issue then?
With each carrier having there own model?
Click to expand...
Click to collapse
lol that does raise new problems that didnt exist before.. i dont know what frequencies you guys will use, but i dont think that really matters much.. every carrier will have their own radio im sure. but as long as the rest of the phone is the same, development wont matter.. just as you can flash firmware XXYZ with modem XXAB and there wont be any problems, you could flash SGS4 firmware XXXDA with any number of modems.
its also possible that samsung could release a modem with multi regional support, so all carriers could use it.. but i dont really see this happening.
As well as using different frequencies, the USA uses two completely technologies namely gsm and CDMA.
Maybe in time, the chips used in phones will be small enough to work on all the frequencies/technologies.
S
Sent from my iPad using Tapatalk (how ironic is that eh)
Hello guys, I'm new here.
I would like to know which one is the best Android to use in bad signal conditions (wich one has the best signal receive and transmit power, that could maintain a call or Internet connection in poor signal). Not just in a specific band or frequency, but in overall.
Thank you.
You mean the phone?
The lastest Android version is always the best if you mean in term of android version.
Peak.Krittin said:
You mean the phone?
The lastest Android version is always the best if you mean in term of android version.
Click to expand...
Click to collapse
No, I mean in phones model.
I was in bus, in a place where my Sony Xperia Z3 does not even recognize network (config> mobile> service providers>nothing shows up), and there was a guy speaking on the phone(He was using a case but I think it is a Motorola), wich indicates that phone could receive, transmit and maitain a better signal than mine. That is why I would like to know wich one is the best in this question.
I would have Huawei, Moto, Honor.
I was able to flash my XQ-BC62 (US) model with the XQ-BC42 (JP) firmware using newflasher. Everything seems to work OK except the mobile radio. The radio is completely disabled (as reported by *#*#4636#*#* status screens), not just unable to connect. The hardware is still fine since flashing back to XQ-BC62 firmware gets a signal again.
Unfortunately I need to use XQ-BC42 as the other firmware images are missing the VoLTE support for my JP carrier and it fails to provision. At best I can force it into data only mode by setting radio to LTE only. The carrier does not support 3G at all.
Extra steps I tried:
- Perform factory reset after flashing
- Swap out the files for the modem firmware from the US firmware and reflash
Has anyone had luck with this, or are there any additional steps I might need to try?
This phone keeps getting worse. I literally bought it to use in the US and Japan. Sony support said it is officially unsupported by all US telcos. No SA 5G, no VoNR, no VoWiFi. Now I hear that it doesn't work in Japan?!
I already know it's close to useless in French Polynesia despite having all the right radio bands.
You can try swapping both OEM-xxx.sin files from the XQ-BC42 firmware folder into the XQ-BC62 firmware folder and flash there XQ-BC62 firmware with that, then you should be able to get VoLTE and modem working at the same time.
If that doesn't work, there are other methods but they will require root access.
kevinmcmurtrie said:
This phone keeps getting worse. I literally bought it to use in the US and Japan. Sony support said it is officially unsupported by all US telcos. No SA 5G, no VoNR, no VoWiFi. Now I hear that it doesn't work in Japan?!
I already know it's close to useless in French Polynesia despite having all the right radio bands.
Click to expand...
Click to collapse
Might you elabortate a bit on this?
So which modell? which provider? comeing form a country where all of these 5G related features are just in development this would be nice to get some further informations on this topic.
VoWiFi is highly likely a provider "problem" - as we have another thread here where these "offical support" statements are at least highly questionable, as we have multiple users here using VoWiFi.
Here is one example of an answer one got from sony
T-Mobile USA Volte and VoWifi support?
Hey XDA, is USA model XQBC62 work with T-Mobile Volte and VoWifi? PS: my old Xperia5 II wasnt able to work and returned back to Sony week later (sad)
forum.xda-developers.com
What is not working in French Polynesia?
Which carrier are you talking about? using a second sim card or use roaming capabilites? keep in mind that not all providers might allow access to all availeable networks based on there roaming contracts. just to give you a idea check these information from one of the providers over ther
https://www.vini.pf/sites/default/files/docs/liste_partenaires_vini-roaming_dec17.pdf
I took my device through several countries already not one having trouble with connectivity as long as the bands are supported and there.
On my trips to japan i head several different devices with me over the yeras, beside the xperia, not once having problems as long as the bands where supported / one is using a local sim - card.
cjmovie said:
Unfortunately I need to use XQ-BC42 as the other firmware images are missing the VoLTE support for my JP carrier and it fails to provision. At best I can force it into data only mode by setting radio to LTE only. The carrier does not support 3G at all.
Click to expand...
Click to collapse
Did you try to get in contact with the japanese carrier asking if they are supporting VoLTE for devices from other markets?
Maybe the easiest way would to switch your carrier at all.
If you are willing to dig around more you could try something like this
5II/1&5III VoLTE patch. [Guide to release the root]
In the Xperia user group in cafe.naver.com/x1smart I'm HTCMAGE. Last year, Xperia 1II. How to activate VoLTE. After the guide version...
forum.xda-developers.com
But you will need the profiles for your vendor. One could play around and try to integrate these profiles into your XQ-BC62 Firmware and see if this would work out. But well - keep fingers crossed that you don't brick anything.
OhayouBaka said:
You can try swapping both OEM-xxx.sin files from the XQ-BC42 firmware folder into the XQ-BC62 firmware folder and flash there XQ-BC62 firmware with that, then you should be able to get VoLTE and modem working at the same time.
If that doesn't work, there are other methods but they will require root access.
Click to expand...
Click to collapse
I'll give this a try and report back. Thanks!
Hudrator said:
Did you try to get in contact with the japanese carrier asking if they are supporting VoLTE for devices from other markets?
Maybe the easiest way would to switch your carrier at all.
Click to expand...
Click to collapse
No, they don't support overseas models. I don't know if it's ignorance around the security or an attempt to prop up their own phone sales. Both are honestly believable over here.
This is the only reasonably priced major carrier plan with unlimited international roaming included (ahamo from NTT Docomo). Not being able to use the 1 iii sucks but I'll just write the 1 iii off if it can't be fixed and continue using my JP variant 1 ii.
cjmovie said:
I'll give this a try and report back. Thanks!
No, they don't support overseas models. I don't know if it's ignorance around the security or an attempt to prop up their own phone sales. Both are honestly believable over here.
This is the only reasonably priced major carrier plan with unlimited international roaming included (ahamo from NTT Docomo). Not being able to use the 1 iii sucks but I'll just write the 1 iii off if it can't be fixed and continue using my JP variant 1 ii.
Click to expand...
Click to collapse
sad to hear - but just out of curiosity:
Why did you get yourself the "American" Variant? Docomo has, as well as softbank, there own supported devices. Kind of similar to TMobile US. Sounds you are spending most of the time in japan. I know that the Docomo version isn't so well supported regarding updates though ...
Hudrator said:
Might you elabortate a bit on this?
So which modell? which provider? comeing form a country where all of these 5G related features are just in development this would be nice to get some further informations on this topic.
VoWiFi is highly likely a provider "problem" - as we have another thread here where these "offical support" statements are at least highly questionable, as we have multiple users here using VoWiFi.
Here is one example of an answer one got from sony
T-Mobile USA Volte and VoWifi support?
Hey XDA, is USA model XQBC62 work with T-Mobile Volte and VoWifi? PS: my old Xperia5 II wasnt able to work and returned back to Sony week later (sad)
forum.xda-developers.com
What is not working in French Polynesia?
Which carrier are you talking about? using a second sim card or use roaming capabilites? keep in mind that not all providers might allow access to all availeable networks based on there roaming contracts. just to give you a idea check these information from one of the providers over ther
https://www.vini.pf/sites/default/files/docs/liste_partenaires_vini-roaming_dec17.pdf
I took my device through several countries already not one having trouble with connectivity as long as the bands are supported and there.
On my trips to japan i head several different devices with me over the yeras, beside the xperia, not once having problems as long as the bands where supported / one is using a local sim - card.
Did you try to get in contact with the japanese carrier asking if they are supporting VoLTE for devices from other markets?
Maybe the easiest way would to switch your carrier at all.
If you are willing to dig around more you could try something like this
5II/1&5III VoLTE patch. [Guide to release the root]
In the Xperia user group in cafe.naver.com/x1smart I'm HTCMAGE. Last year, Xperia 1II. How to activate VoLTE. After the guide version...
forum.xda-developers.com
But you will need the profiles for your vendor. One could play around and try to integrate these profiles into your XQ-BC62 Firmware and see if this would work out. But well - keep fingers crossed that you don't brick anything.
Click to expand...
Click to collapse
I have the US model - the same as this thread topic.
It's Sony tech support themselves that told me that there is no carrier support for the US model in the US. It was such an incredible conversation that I saved it. An excerpt:
(Adrian) said :I'm asking you this because at this moment Verizon is currently the only U.S. carrier that supports 5G on the Xperia PRO model. The 5G network service is
not currently available in the Xperia 1 III model and this is why you're getting that
issue. In this particular case we recommend you to check with your phone carrier
if there is a way for them either to provide a different network service or if there is
a work around on their system for you to use your Xperia phone with their service
Click to expand...
Click to collapse
Don't repeat Sony's claim about 5G being in development. T-Mobile has been running SA 5G where I live for nearly 2 years. I've done side-by-side comparisons between an older phone with SA 5G and my Xperia by swapping the SIM. The XPeria has a lot of "no service" problems because it's using SA 5G channel aggregations without having SA 5G. There's another thread on this - Sony has explicitly disabled SA 5G on all US NR bands. https://cacombos.com/device/XQ-BC62
The Sony phone was unstable roaming in PF and could not see several 3G, LTE, and 5G bands that were available to it. Again, an older phone worked better. I used a much more modern coverage map than your 2017 document.
I haven't been to Japan with this my Xperia yet due to COVID restrictions, but I normally spend ~2 weeks a year there. I know my old phone works well there so I'm going to be mad if a new Xperia is stuck looking for old 3G cells that only exist in subways.
I have an XQ-BC42 that I'm using in Europe with 5G working (which isn't supported officially).
All I had to do was flash the XQ-BC42 firmware with the following 3 files replaced by their equivalents from the XQ-BC52 firmware:
* modem_X-FLASH-ALL-4BA8.sin
* modemst1_X-FLASH-ALL-4BA8.sin
* modemst1_X-FLASH-ALL-4BA8.sin
So in your case you just have to take the 3 files above from the XQ-BC42 firmware and combine them with everything else from XQ-BC62 firmware and flash that.
From what I've gathered, assuming your phone has XQ-BC62 firmware on it already, it might only be necessary to flash the XQ-BC42 modem files and nothing else, but I haven't tested this.
I'm assuming you can swap other files too but what definitely didn't work for me was the oem .sin files from another model's firmware. I don't know if there's something incompatible about the XQ-BC42 compared with other models but using non-XQ-BC42 oem .sin files disabled my radio completely.
kevinmcmurtrie said:
I have the US model - the same as this thread topic.
It's Sony tech support themselves that told me that there is no carrier support for the US model in the US. It was such an incredible conversation that I saved it. An excerpt:
Don't repeat Sony's claim about 5G being in development. T-Mobile has been running SA 5G where I live for nearly 2 years. I've done side-by-side comparisons between an older phone with SA 5G and my Xperia by swapping the SIM. The XPeria has a lot of "no service" problems because it's using SA 5G channel aggregations without having SA 5G. There's another thread on this - Sony has explicitly disabled SA 5G on all US NR bands. https://cacombos.com/device/XQ-BC62
The Sony phone was unstable roaming in PF and could not see several 3G, LTE, and 5G bands that were available to it. Again, an older phone worked better. I used a much more modern coverage map than your 2017 document.
I haven't been to Japan with this my Xperia yet due to COVID restrictions, but I normally spend ~2 weeks a year there. I know my old phone works well there so I'm going to be mad if a new Xperia is stuck looking for old 3G cells that only exist in subways.
Click to expand...
Click to collapse
no, i am not saying it is under development. The standards are there. How ever - in different regions some of the 5g is still not rolled out / will never been seen (mmWave,SA 5G - at least for private customers).
Well i read the message you quoted a bit different - and i would love to know what other carriers have to say about that.
I personally would find it completly unlogic to sell a device like the Pro, which is said in your excerpt, to have 5G support on Verizon - but then sell the 5G capable phones which have this deactivated at all.
Supported Major U.S. Carriers: Verizon (5G), T-Mobile (4G), AT&T (4G)*
*As of 9/27/2021, please consult with your network operator to ensure compatibility with their network.
Click to expand...
Click to collapse
Source:
Sony Electronics
electronics.sony.com
Might be, that t-mobile is using some more advanced features. how ever: here where i live most phones up to now don't support 5G SA, at least thats what the carriers say, as there are updates needed to make this work. So we will see here some selected phones using 5G SA - as the providers are working together with SOME of the major OEMs.
You can know ask who is responsible for supporting 5G SA or providing updates... As much as i got from t-mobile usa, they where always not really open to devices, which they don't sell directly ....
Hudrator said:
sad to hear - but just out of curiosity:
Why did you get yourself the "American" Variant? Docomo has, as well as softbank, there own supported devices. Kind of similar to TMobile US. Sounds you are spending most of the time in japan. I know that the Docomo version isn't so well supported regarding updates though ...
Click to expand...
Click to collapse
I happened to be in the US at the time to pre-order and it wasn't clear that Sony would release an unlocked dual-SIM model for the JP market. I checked the radio bands before purchasing but all of this client provisioning stuff is new to me. Seems like all these laws were made to force carriers to unlock their phones / allow any standards compliant phone on their networks, and then they find this loophole with provisioning that requires more than just a SIM card...
OhayouBaka said:
You can try swapping both OEM-xxx.sin files from the XQ-BC42 firmware folder into the XQ-BC62 firmware folder and flash there XQ-BC62 firmware with that, then you should be able to get VoLTE and modem working at the same time.
If that doesn't work, there are other methods but they will require root access.
Click to expand...
Click to collapse
Unfortunately this didn't work. But I did learn that the radio problem isn't an issue with the firmware itself.
Immediately after flashing the mobile radio was OK and I could use it with my alternate SIM card. As soon as I inserted the JP SIM card it triggered OMA client provisioning and killed the radio. After this happened not even the US SIM card would work anymore, and any radio related configurations can no longer be changed.
My hypotheses at this point are either (a) the client provisioning step found something off with my phone and forced it to lock down (not sure if client provisioning has the authority to do this though), (b) the client provisioning is interacting with the modem firmware in a JP-specific way and the US modem firmware is borked by this.
playstation360 said:
I have an XQ-BC42 that I'm using in Europe with 5G working (which isn't supported officially).
All I had to do was flash the XQ-BC42 firmware with the following 3 files replaced by their equivalents from the XQ-BC52 firmware:
* modem_X-FLASH-ALL-4BA8.sin
* modemst1_X-FLASH-ALL-4BA8.sin
* modemst1_X-FLASH-ALL-4BA8.sin
So in your case you just have to take the 3 files above from the XQ-BC42 firmware and combine them with everything else from XQ-BC62 firmware and flash that.
From what I've gathered, assuming your phone has XQ-BC62 firmware on it already, it might only be necessary to flash the XQ-BC42 modem files and nothing else, but I haven't tested this.
I'm assuming you can swap other files too but what definitely didn't work for me was the oem .sin files from another model's firmware. I don't know if there's something incompatible about the XQ-BC42 compared with other models but using non-XQ-BC42 oem .sin files disabled my radio completely.
Click to expand...
Click to collapse
Other than the issue after provisioning the OEM files from the JP model did work for me. If (b) is true then flashing both the oem and modem files might be a solution. I'll give that a try!
playstation360 said:
I have an XQ-BC42 that I'm using in Europe with 5G working (which isn't supported officially).
All I had to do was flash the XQ-BC42 firmware with the following 3 files replaced by their equivalents from the XQ-BC52 firmware:
* modem_X-FLASH-ALL-4BA8.sin
* modemst1_X-FLASH-ALL-4BA8.sin
* modemst1_X-FLASH-ALL-4BA8.sin
So in your case you just have to take the 3 files above from the XQ-BC42 firmware and combine them with everything else from XQ-BC62 firmware and flash that.
From what I've gathered, assuming your phone has XQ-BC62 firmware on it already, it might only be necessary to flash the XQ-BC42 modem files and nothing else, but I haven't tested this.
I'm assuming you can swap other files too but what definitely didn't work for me was the oem .sin files from another model's firmware. I don't know if there's something incompatible about the XQ-BC42 compared with other models but using non-XQ-BC42 oem .sin files disabled my radio completely.
Click to expand...
Click to collapse
cjmovie said:
Other than the issue after provisioning the OEM files from the JP model did work for me. If (b) is true then flashing both the oem and modem files might be a solution. I'll give that a try!
Click to expand...
Click to collapse
Same result, no radio after client provisioning runs and it stays borked even with the SIM card swapped out.
cjmovie said:
Same result, no radio after client provisioning runs and it stays borked even with the SIM card swapped out.
Click to expand...
Click to collapse
Have you tried with only the modem files taken from the XQ-BC42 firmware? Might be worth a shot.
Also, it might be worth asking on the 5ch thread if you speak Japanese.
playstation360 said:
Have you tried with only the modem files taken from the XQ-BC42 firmware? Might be worth a shot.
Also, it might be worth asking on the 5ch thread if you speak Japanese.
Click to expand...
Click to collapse
I spent a few more days trying various combinations of flashing, factory resets, etc. and finally have it working. I don't know if this is the only way to achieve this, but I can share the sequence I did most recently. This was inspired by the discussions in that 5ch thread - thanks for the link!
1. Install JP variant ROM with full factory reset.
2. Install the JP SIM card and wait for provisioning to finish. The radio stops working at this point.
3. Create and flash a hybrid ROM, using the modem*.sin files from the JP variant and everything else from the original (US) variant. Do NOT factory reset.
4. Set the correct APN (sp-mode.net for ドコモ).
After this both the JP and US SIM cards are working.
@cjmovie
Congrats on this achievement! Hope you can now use your device as you wished!
Hello,
I got an Xperia 5 IV in February and I love it. However, there is a pretty significant problem with it. I am not about to use data while on a phone call and since I do not have any Wi-Fi where I live, this was pretty much a deal breaker. I even bought a second Sony Xperia 5 IV hoping that the problem was just a flawed model. I'll be returning one of the phones shortly, but having two devices has given me the benefit of being able to experiment.
My carrier is Cricket Wireless, which is an MVNO of AT&T. I knew the problem with data while on a call was not Cricket's fault, because I had used the exact same SIM card on other devices and there was no problem. I then got into flashing for the very first time and I flashed some European firmware using XperiFirm and thankfully, the problem was solved. However, I did notice that the RAM management was worse on the phone with American firmware compared to the phone with European firmware. I then remember watching a review for the Sony Xperia 5 IV on YouTube and the reviewer, who was Irish, complained about the RAM management. When I got my phone initially, I never noticed the RAM problem at all, only the data while calling problem. Because I have two Xperia 5 IVs, I was able to test and verify that indeed, the RAM management on European firmware is worse compared to American firmware.
I flashed Asian firmware onto the phone, hoping that the result would be me being able to use my Sony phone without any compromise, i.e., being able to use data while on a call and have a superb RAM experience. Strangely enough, my SIM card was not recognized. I am aware that AT&T has a whitelist, but the whitelist only includes the American model number and the service worked without a hitch on European firmware.
I am just not sure why this is the case or if there is perhaps any resolution to this problem?
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