Is it possible to downgrade while keeping current BL - Samsung Galaxy S9+ Questions & Answers

Hello!
First of all, I'm a novice and have no knowledge of how the firmware is constructed, e.g. wrt any dependencies between BL, AP, CP and CSC. I've searched the S9+ forums without finding answers - I have however found threads concerning downgrading but they seem not to answer my exact question.
I'm currently on the latest build of Android 10 for my region (SM-G965F, 965FXXU7DTAA). Completely stock, no modifications.
I read in an S7 thread that someone had been able to downgrade to a previous FW version with a lower BL version than the phone currently was on by doing the following:
- downloading and extracting the FW wanted
- removing the sboot and the modem parts of the firmware
- repacking the remaining parts
- flashing with odin
According to him/her, this worked, the phone booted succesfully, even though he/she at that point hadn't yet tested it to the full extent and in all aspects.
My question: Would this even be possible for the S9+? I.e. only flashing the AP and CSC parts of the desired FW via Odin while leaving BL and CP parts untouched? Would it even work, and if so, is it possible to say/know anything about adverse effects. Is the phone likely to brick? Knox?
Excuse me if this is obvious to you all, but I'm curious about this as I am currently not satisfied with Android 10.
I should add that I'm aware that it is currently possible to downgrade to latest version of Pie the "regular way", but I'm looking for options, if any, to go even further back
Rgds,
sten_amund

sten_amund said:
Hello!
First of all, I'm a novice and have no knowledge of how the firmware is constructed, e.g. wrt any dependencies between BL, AP, CP and CSC. I've searched the S9+ forums without finding answers - I have however found threads concerning downgrading but they seem not to answer my exact question.
I'm currently on the latest build of Android 10 for my region (SM-G965F, 965FXXU7DTAA). Completely stock, no modifications.
I read in an S7 thread that someone had been able to downgrade to a previous FW version with a lower BL version than the phone currently was on by doing the following:
- downloading and extracting the FW wanted
- removing the sboot and the modem parts of the firmware
- repacking the remaining parts
- flashing with odin
According to him/her, this worked, the phone booted succesfully, even though he/she at that point hadn't yet tested it to the full extent and in all aspects.
My question: Would this even be possible for the S9+? I.e. only flashing the AP and CSC parts of the desired FW via Odin while leaving BL and CP parts untouched? Would it even work, and if so, is it possible to say/know anything about adverse effects. Is the phone likely to brick? Knox?
Excuse me if this is obvious to you all, but I'm curious about this as I am currently not satisfied with Android 10.
I should add that I'm aware that it is currently possible to downgrade to latest version of Pie the "regular way", but I'm looking for options, if any, to go even further back
Rgds,
sten_amund
Click to expand...
Click to collapse
admittedly, i TL : DR all of it, but on the S7, downgrading the bootloader was possible for a while, thats not the case here. You can only flash F/W with the same or higher BL version. If there is an android 9 version available with the same BL, then you can flash it all you like. www.sammobile.com/firmwares is where you need to go to look. But use the frija tool or SamFirm to actually d/l the zip unless you like wasting 2 hours of your life

Thanks for the reply
I'm aware that I am able to downgrade to the latest version of Pie, which has the same version BL as my current Android 10. But my question is rather if it is possible at all to flash only the AP and CSC sections of a previous FW (with lower BL version) and leave the current Android 10 BL and AP untouched as it is on the phone?
Sorry if I was unclear in my first post
Rgds,
sten_amund

sten_amund said:
Thanks for the reply
I'm aware that I am able to downgrade to the latest version of Pie, which has the same version BL as my current Android 10. But my question is rather if it is possible at all to flash only the AP and CSC sections of a previous FW (with lower BL version) and leave the current Android 10 BL and AP untouched as it is on the phone?
Sorry if I was unclear in my first post
Rgds,
sten_amund
Click to expand...
Click to collapse
As long as the previous firmware is the same bit number you can flash either. You would have to flash all the files as the 10 bootloader more than likely isn't going to boot pie. 5th Digit from the far end of build is your bit number.

Thank you for your reply - good input wrt 'bootability'.
I'll downgrade to the latest version of Pie the regular way.
rgds,
sten_amund

Related

Firmware Question

I have a firmware question that I can't seem to find the answer to by searching. I am running arhd 11 on an att HTC one. Should I upgrade the firmware on my phone? Will there be any benefits to this since I am on att and not international? Also how do I go about updating the firmware and does it wipe the device? If I should upgrade, what it's the version I should download? Longtime Samsung user so please excuse the noobness.
If alls running well, then plz avoid ... however, in ARHD thread many AT&T users have updated the firmware without any side-effects
Best to post Q in that thread itself
asjshenry said:
I have a firmware question that I can't seem to find the answer to by searching. I am running arhd 11 on an att HTC one. Should I upgrade the firmware on my phone? Will there be any benefits to this since I am on att and not international? Also how do I go about updating the firmware and does it wipe the device? If I should upgrade, what it's the version I should download? Longtime Samsung user so please excuse the noobness.
Click to expand...
Click to collapse
It is currently not mandatory to flash the new firmware for ARHD, but it does provide a noticeable increase performance depending on the current firmware version you are running, I was running 1.26 on my AT&T m7 and the screen and touch buttons have been much more responsive now that I am running the new 2.24. Flashing the new firmware will also update the baseband, providing you with the latest radio (but performance of this will vary from region to region.
If you go to this link, it will give you some great instructions on the update process.
http://forum.xda-developers.com/showpost.php?p=42556698&postcount=24958
BTW, you will need to be s-off and change your cid to 11111111. As long as you take your time and follow the directions completely you will be fine. If you do update make sure you flash the firmware TWICE when it says to, and make sure you re-flash your custom recovery because it will get replaced during the updating process. This process will not delete your sd card and you will be able to run your current ARHD, but it is recommended to do a clean install after. And you might as well since 12.0 is out.
hope this helps
I'm getting a failed not allowed error when trying to 'fastboot flash zip'
I successfully have s-off and changed CID but can't get firmware to flash
Edit: not sure what happened but I was able to push the zip successfully. Maybe from adding the path of the file instead of just the zip file? Anyway, it worked.
Sent from my HTC One using xda premium
IF the rom is tweaked right theres no real reason to update the firmware to euro build,Id wait till att variant or the dev variant gets the update and then worry about it.

Flashing firmware help

I am going to flash the firmware on my m8 to upgrade to 4.4.4 ARHD but I am still unsure of how to identify the proper firmware zip . Could someone provide some guidance? Attached are some images from the recovery. I'm not sure what numbers I need to match with the firmware zip. And I can't find how to view what numbers are in the zip. Any advice is very much appreciated.
hboot 3.16 corresponds to firmware that deployed with 1.x software. Its what many folks call "1.x firmware" for lack of any better title, since firmware doesn't really have a "number".
If you want to update to the latest ARHD, you need "3.x firmware". Any firmware with number 3.xx.xx will allow the phone to boot normally, and with working WiFi. The numbers after the 3 are just carrier/region specific versions.
But for the AT&T network, you are probably best off flashing the 3.28.1540 firmware posted on WNC's ROM here: http://forum.xda-developers.com/att-htc-one-m8/development/att-4-4-3-2-22-1540-3-debloated-sense-6-t2837365
Thanks a lot!
redpoint73 said:
hboot 3.16 corresponds to firmware that deployed with 1.x software. Its what many folks call "1.x firmware" for lack of any better title, since firmware doesn't really have a "number".
If you want to update to the latest ARHD, you need "3.x firmware". Any firmware with number 3.xx.xx will allow the phone to boot normally, and with working WiFi. The numbers after the 3 are just carrier/region specific versions.
But for the AT&T network, you are probably best off flashing the 3.28.1540 firmware posted on WNC's ROM here: http://forum.xda-developers.com/att-htc-one-m8/development/att-4-4-3-2-22-1540-3-debloated-sense-6-t2837365
Click to expand...
Click to collapse
So even if you just want the new Firmware, you have to do everything in that thread? I'm asking because it shows installing a ROM then doing stuff with Xposed, which I assume will be undone when the ROM changes
badbwoydes said:
So even if you just want the new Firmware, you have to do everything in that thread? I'm asking because it shows installing a ROM then doing stuff with Xposed, which I assume will be undone when the ROM changes
Click to expand...
Click to collapse
No, you just need to perform the steps listed under "Updating firmware" numbered 1-8. And also skip the very last step (Step 8, Substep 3).
The rest is if you want to run the modified Dev Ed ROM, as you have somewhat already figured out. But honestly, if you are on AT&T's network, I would consider the ROM anyway. Many folks (including myself) get various network errors running "international" based custom ROMs; which the debloated Dev Ed ROM does not suffer from.

Recommended bootloader for GT-I9300?

I looked around the internet a lot and wasn't able to find any useful information about this. I have a GT-I9300
I've recently updated my OS (lineage 4.1 - Android 7.1.2) and modem (I9300XXUGMK6) and I'm wondering what a recommended boot-loader might be. I chose this modem because it was listed on the ROM page, and it seems to work fine.
I found this but it appears to be very old:
https://forum.xda-developers.com/galaxy-s3/general/ref-galaxy-s3-stock-kernel-bootloaders-t2189063
Before I updated, my modem was version I9300XXEMG4, and I'm pretty sure I updated my modem and boot-loader at the same time previously, which leads me to believe my boot-loader is probably XXEMG4 too (assuming that exists).
Should I update to XXEMG5? Should I try to find the boot-loader that corresponds to my modem (XXUGMK6, assuming that exists)?
I just want something that is probably going to be reliable, not that I have any specific problems, but I believe in staying up to date. Where can I find the latest boot-loaders? Any reason not to just get the latest? What are people here using in general?
The bootloader doesn't need to be changed and you cannot downgrade once you've updated the firmware to mk6 unless you have a backup of your efs from before mk6.
If it ain't broke..
Beamed in by telepathy.
Ok, it seems to be running fine since I upgraded the modem. Thanks.

Where to find old firmware/How to backup firmware?

As I understand it, I don't need to unlock the bootloader in order to flash different official firmware versions to my phone. I'm leaving the bootloader locked until I really have a need to unlock it, because of the long-shot hope for a root exploit that will let me preserve my TA partition. As part of that, I really don't want to be stuck on a recent firmware version with all the old security holes patched. Therefore I want to get ahold of my current firmware or earlier before I flash anything. Somebody stop me here if I've misunderstood and anything I've said so far is impossible.
I have the dual-sim variant, G8342, running firmware 47.1.A.2.324.
Question 1: Is there a source somewhere of archived XZ1 firmware versions that includes 47.1.A.324 or earlier? I have searched the forum and google, but most xperia firmware backup sites have little or no files for the XZ1, and the couple of sources I've found are ancient with broken links. The post on these forums with stock firmware downloads only includes much newer versions.
Question 2: Is there a way I can extract a copy of my current firmware from my phone, without unlocking the bootloader? I find tutorials that work for "any xperia", but they're all quite old and talk about Sony PC Companion instead of Xperia Companion, and they all involve clicking "Your software is up to date"--and my software is not up to date, and updating it before backing it up would defeat the entire purpose of backing it up.
I'd greatly appreciate it if someone could clarify this for me so I can flash new firmware without losing the ability to go back.
Hi there, sorry i can't help you with your questions. I have one more question actually. are you sure i don't have to unlock bootloader if i flash official stock firmware??
Opposite to you, i'm stuck with a really old build from 2017. my phone is xz1 and its build version is 47.1.A.2.374. android security patch is from october 2017 and i desperately want to update the newest firmware yet i'm always told that my firmware is lastest.
sooo, am i able to flash it with the flashtool or newflasher?/
thank you
xperia_sony_best said:
Hi there, sorry i can't help you with your questions. I have one more question actually. are you sure i don't have to unlock bootloader if i flash official stock firmware??
Opposite to you, i'm stuck with a really old build from 2017. my phone is xz1 and its build version is 47.1.A.2.374. android security patch is from october 2017 and i desperately want to update the newest firmware yet i'm always told that my firmware is lastest.
sooo, am i able to flash it with the flashtool or newflasher?/
thank you
Click to expand...
Click to collapse
Seems highly unlikely that you haven't received an update since 2017 but then stranger things have happen.. New phone, carrier branded hmm..
Have you tried to update with Sony Companion, use the software update on the phone its self..
Oh and yes you can use the other methods you have mentioned..
lilbrat said:
Seems highly unlikely that you haven't received an update since 2017 but then stranger things have happen.. New phone, carrier branded hmm..
Have you tried to update with Sony Companion, use the software update on the phone its self..
Oh and yes you can use the other methods you have mentioned..
Click to expand...
Click to collapse
thanks god i found a solution for this.
Repair my phone using xperia companion.
it's basically like flashing my phone and update my firmware to the latest firmware which is 47.1.A.16.20
Thanks God (or curious me )
either way, i found a way to update my phone without using flashtool. hope this will help someone in the future
Check here:
https://drive.google.com/drive/folders/1Yu3WP7yiO3TJuEiQvhEQ-zq53LcPdYIU
Thanks a ton, lionelbac! For anyone else who comes across this thread, there's now also a download of 47.1.A.2.281_CE1 available in j4nn's magnificent TA partition backup thread, since that firmware is necessary for his exploit to work: https://forum.xda-developers.com/xperia-xz1-compact/development/devonly-exploits-temp-root-to-backup-t3795510
lionelbac said:
Check here:
Where to find old firmware for xz1 g8341 customized CH?
thank!
Click to expand...
Click to collapse
willynguyen said:
lionelbac said:
Check here:
Where to find old firmware for xz1 g8341 customized CH?
thank!
Click to expand...
Click to collapse
No idea, I found that site googling.. Somewhere in the web could be another repository for your version. Good luck!
Click to expand...
Click to collapse

F900U and F900U1 Firmware Links Here

For those who don't know, F900U is the model number of all of the US carrier versions of the Galaxy Fold. The F900U1 is the model number of the same device, but sold by Samsung SIM unlocked and with no carrier bloatware. Firmware is 100% interchangeable among these models: any U or U1 firmware version can be flashed to any U or U1 device at any time, assuming that you're not trying to downgrade the bootloader. A "U to U" or "U1 to U1" flash does not require a factory reset, but changing from one firmware to the other will require one. Also, U firmware is identical for the 4 base files (AP, BL, CP, CSC) for each individual build, no matter which carrier it comes from. So if you download 2 different carrier versions of the exact same build, the 4 base files will be identical. Where the firmware differs is in the USERDATA file - that's where the carrier bloatware and customizations reside.
Manual Odin flashing is designed for those who:
- want to manually update to a newer version of U firmware on their U device, either because they don't want to wait for their carrier's OTA or because OTAs aren't working on their device, or a different carrier got a new feature/patch before they did
- want to flash U1 firmware to their U device
- want to convert from U1 firmware to carrier U firmware
- want to convert from one carrier's U firmware (with all apps and bloatware) to a different carrier's U firmware (with all apps and bloatware)
For those who aren't already aware, anyone can now download firmware for almost any Samsung device any time that they want, via SamFirm or Frija. There are threads and info about them here on XDA so I won't waste time explaining - do a search if you're not already familiar with these tools. But AT&T doesn't allow their firmware to be publicly available (for any of their devices). I pay for a subscription to a site that gets the official releases (usually) before they hit SamFirm/Frija, and also gets me access to AT&T firmware, so that's where my files come from. However, I don't have unlimited bandwidth on the site, and it's also quite time consuming to download the files, zip them up, and upload them to AFH. And, I do threads like this for every single Sx and Note x model - so I won't be uploading every single version. I'll definitely do at least one build per bootloader level though.
This is not a "beginner's guide to Odin flashing"-type post/thread, so I won't list basic, step-by-step instructions. My threads are geared towards those who already know what they're doing. If you're new to manually flashing Samsung firmware, I recommend you consult one of the "beginner's" posts/threads - there are tons of them here on XDA.
U firmware: https://www.androidfilehost.com/?w=files&flid=293117
U1 firmware: https://www.androidfilehost.com/?w=files&flid=293118
Happy flashing!
Notes:
- DON'T QUOTE THE OP WHEN YOU REPLY, kthx
- I compress extra small for space and bandwidth savings. The default Windows extractor can't handle it, so you'll need a 3rd party tool like 7zip, WinRAR, etc
- My naming method for Android File Host folders is: build - bootloader - Android version.
So "SAT - 1 - 9.0" means the full build number ends in SAT, it's bootloader version 1, and Android 9.0. When bootloader and Android versions increment, the first build to have those changes will have its folder notated appropriately.
- HOME CSC file keeps data intact; using the other CSC will wipe data.
- I pay for a subscription to a site that gets beta builds and also sometimes gets the official releases before they hit SamFirm, so that's where any of my files come from. I will only be posting versions that I get early access to, and USERDATAs that aren't available on SamFirm or Frija (AT&T). The newest/latest firmware files for all carriers other than AT&T can always be obtained via SamFirm and Frija.
- For USERDATAs (all the others are self explanatory):
AIO = Cricket
CCT = Xfinity Mobile (Comcast)
CHA - Spectrum Mobile (Charter)
TMK = Metro PCS
- the correct procedure for switching from one carrier's firmware to another is:
1. Flash full U1 firmware package including non HOME CSC
2. Upon boot, insert a SIM of the carrier whose firmware you want
3. Watch for the popup that says "reboot to apply new carrier settings" etc, and do it
4. After that restart completes, reboot back to Download mode and flash the full U firmware package, with the USERDATA file of the carrier whose firmware you want
Interesting development, as we approach the release date for the now-redesigned Fold: U1 firmware has appeared!
I have no idea if they were planning for a U1 model all along, but that firmware never showed up earlier this year. I still haven't seen any new U firmware, but assuming that I get access to at least the launch version before the actual release, I'll post it when I get it
Build SH9 has appeared for the U model, along with an AT&T USERDATA. Files have been uploaded to the OP link
Will SHA get OTA to SH9?
mastibeta said:
Will SHA get OTA to SH9?
Click to expand...
Click to collapse
I don't understand your question.
First of all, numbers come before letters. 9 is older than A. If SH9 and SHA were both released for the same model, then SH9 would come first, and then there would be an OTA to SHA.
But SH9 is U firmware and SHA is U1. You can't OTA to a different model's firmware.
iBowToAndroid said:
I don't understand your question.
First of all, numbers come before letters. 9 is older than A. If SH9 and SHA were both released for the same model, then SH9 would come first, and then there would be an OTA to SHA.
But SH9 is U firmware and SHA is U1. You can't OTA to a different model's firmware.
Click to expand...
Click to collapse
Gotcha, didnt realize the u1 was newer. Do you know what CSC frija would have the u1 firmware under?
mastibeta said:
Gotcha, didnt realize the u1 was newer. Do you know what CSC frija would have the u1 firmware under?
Click to expand...
Click to collapse
XAA is always used for U1 firmware. Manual input is required in order to get it, as of right now. They'll probably change that once the device actually releases
Morning. I cant get these files to download. It's been about 30 min and the download says 6 days.
NEVER MIND. After about an hour it went form six days to finished. Lol.
harsaphes said:
Morning. I cant get these files to download. It's been about 30 min and the download says 6 days.
NEVER MIND. After about an hour it went form six days to finished. Lol.
Click to expand...
Click to collapse
AFH's servers are crap, half of the time. If you ever get a slow download, just reload the link and try a different mirror
Really want to do this but have never flashed any type of Samsung software before. Was checking guides but none of them seemed exact. Don't want to Brick my fold and even though I have AT&T I don't want to be behind on updates and have bloatware.
alexrotondo said:
Really want to do this but have never flashed any type of Samsung software before. Was checking guides but none of them seemed exact. Don't want to Brick my fold and even though I have AT&T I don't want to be behind on updates and have bloatware.
Click to expand...
Click to collapse
It's impossible to brick it. And yes, there are tons of very precise and exact Odin flashing guides here on XDA. Odin flashing is always pretty much the same process, no matter the model. Put the phone in Download, make sure you have the right Odin version, extract the zip, load all the files, plug the phone in, and click Start
What is the site you pay a subscription for?
I have a small question... will I brick the Fold, if I flash this to the Korean Version of the Fold (SM-F907N)?
The only version I could buy in where I live is the Korean version, which is a 5G model, but I really want to use my credit cards from USA. I guess I have to have a Fold with USA firmware to use Samsung Pay with credit card from USA, but I don't know what would happen if I flash this firmware... I am okay with losing the 5G, I just want the Samsung Pay works with my credit cards...
STEVEcKONG said:
I have a small question... will I brick the Fold, if I flash this to the Korean Version of the Fold (SM-F907N)?
The only version I could buy in where I live is the Korean version, which is a 5G model, but I really want to use my credit cards from USA. I guess I have to have a Fold with USA firmware to use Samsung Pay with credit card from USA, but I don't know what would happen if I flash this firmware... I am okay with losing the 5G, I just want the Samsung Pay works with my credit cards...
Click to expand...
Click to collapse
You can't flash it. Odin won't allow you to, because those models are not cross compatible. If you want a Fold that does US Samsung Pay, buy one from the US and have it shipped to you
iBowToAndroid said:
You can't flash it. Odin won't allow you to, because those models are not cross compatible. If you want a Fold that does US Samsung Pay, buy one from the US and have it shipped to you
Click to expand...
Click to collapse
Thanks a lot!
Hmm....after I download the F900U1 file the folder says 'empty'.
On the download link the U1 folder says no files. Am I looking in the wrong place?
Trying this again.
OK GOT IT. THANKS
harsaphes said:
On the download link the U1 folder says no files. Am I looking in the wrong place?
Click to expand...
Click to collapse
You must be. I can see it perfectly clear, when I click the U1 link in the OP
Any update on successfully flashed u1 firmware on att fold? Wanting to pick up unlocked one but only the att version is available
I just did mine . If you need help let me know
svickory said:
I just did mine . If you need help let me know
Click to expand...
Click to collapse
sent you a message, have a question or two.

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