LTE speed between MIUI and custom ROM - Xiaomi Poco F1 Questions & Answers

Hello,
firstly I apologize in the advance if there is a such thread made for this issue and if I opened the thread in the wrong location.
Now, regarding the issue is with the LTE speed between original MIUI and custom ROM. I have tried all custom ROMs: Lineage OS, Havoc OS, Nitrogen OS and Pixel Experience. All are working perfectly with one big downside and that is LTE speed. With MIUI I get full LTE speed about 50-70Mbps, HOWEVER with all custom ROMs I get LTE speed strictly limited to 4-5Mbps for unknown reason. I flashed different vendor firmware version, I even tried with root and without root. Sadly I got same results.
All I know that custom ROM is based on AOSP so I assume there is something missing something. I live in Europe, in country Slovenia.
Is there anything worth trying to fix LTE speed in custom ROMs? I have the global version Pocophone F1.
Thanks in the advance for the help.

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LOL!! 50-70MBPS?? Do you actually see 50mbps while downloading or uploading? If yes, I would like to see some proof like a screenshot where a big file is getting downloaded on Google Chrome and the speed is showing 50MB/S. FYI, there's a huge difference between speed on a speedtest app and in real life usage. I have never noticed any speed difference in between PE and MIUI in real world. Maybe that's because I don't believe in fake results on SpeedTest apps.

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Rowdyy Ronnie said:
LOL!! 50-70MBPS?? Do you actually see 50mbps while downloading or uploading? If yes, I would like to see some proof like a screenshot where a big file is getting downloaded on Google Chrome and the speed is showing 50MB/S. FYI, there's a huge difference between speed on a speedtest app and in real life usage. I have never noticed any speed difference in between PE and MIUI in real world. Maybe that's because I don't believe in fake results on SpeedTest apps.
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Um... I didn't write MBps.... I wrote Mbps and those two units are not same... 50-70Mbps is equivalent to approx. 6-9MBps download speed. Well, to show the proof, I need to reflash MIUI again which I don't want it for now. I tried downloading any apps, files, movies, music... etc on Opera, Chrome, Firefox in all custom ROMs. All were shown to 500-600KBps download speed. I'm currently on Havoc OS.

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Karibes said:
Um... I didn't write MBps.... I wrote Mbps and those two units are not same... 50-70Mbps is equivalent to approx. 6-9MBps download speed. Well, to show the proof, I need to reflash MIUI again which I don't want it for now. I tried downloading any apps, files, movies, music... etc on Opera, Chrome, Firefox in all custom ROMs. All were shown to 500-600KBps download speed. I'm currently on Havoc OS.
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Can be a possibility of not getting Carrier Aggregation (4g+ or 4G LTE CA) problem on custom roms? Do you see 4g+ on custom roms? I'm on custom rom and getting 70-80Mbps (7-8MB) download speed .
@Rowdyy Ronnie not sure if you thought OP meant 50-70MBPS or 50-70mbps but I'm easily getting above 70Mbps (7MBps+ download speed) on 4G in India with JIO. Probably poco is the only phone which gives me best 4g speed as compared to other phones I use. This is why my JIO number is always in Poco phone.

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Daruwalla said:
Can be a possibility of not getting Carrier Aggregation (4g+ or 4G LTE CA) problem on custom roms? Do you see 4g+ on custom roms? I'm on custom rom and getting 70-80Mbps (7-8MB) download speed .
@Rowdyy Ronnie not sure if you thought OP meant 50-70MBPS or 50-70mbps but I'm easily getting above 70Mbps (7MBps+ download speed) on 4G in India with JIO. Probably poco is the only phone which gives me best 4g speed as compared to other phones I use. This is why my JIO number is always in Poco phone.
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No, I don't see any 4G+ or 4G LTE CA in any custom ROMs and it is same with MIUI because it also shows 4G, yet in MIUI I get far better download speed... I'm quite confused... Maybe (hopefully) will something change when we switch carrier, though I highly doubt it will change anything.

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Karibes said:
No, I don't see any 4G+ or 4G LTE CA in any custom ROMs and it is same with MIUI because it also shows 4G, yet in MIUI I get far better download speed... I'm quite confused... Maybe (hopefully) will something change when we switch carrier, though I highly doubt it will change anything.
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Click to collapse
Weird bug. Install this app and post LTE 4/2xCA screenshot. I doubt changing carrier would help.
https://play.google.com/store/apps/details?id=com.qtrun.QuickTest&hl=en_IN

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Daruwalla said:
Weird bug. Install this app and post LTE 4/2xCA screenshot. I doubt changing carrier would help.
https://play.google.com/store/apps/details?id=com.qtrun.QuickTest&hl=en_IN
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Click to collapse
Okay, give me a moment.
Edit: which tab do you wish to know?
Edit1: http://prntscr.com/o3jo0c (I hope that's one you were looking for...)

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Karibes said:
Hello,
firstly I apologize in the advance if there is a such thread made for this issue and if I opened the thread in the wrong location.
Now, regarding the issue is with the LTE speed between original MIUI and custom ROM. I have tried all custom ROMs: Lineage OS, Havoc OS, Nitrogen OS and Pixel Experience. All are working perfectly with one big downside and that is LTE speed. With MIUI I get full LTE speed about 50-70Mbps, HOWEVER with all custom ROMs I get LTE speed strictly limited to 4-5Mbps for unknown reason. I flashed different vendor firmware version, I even tried with root and without root. Sadly I got same results.
All I know that custom ROM is based on AOSP so I assume there is something missing something. I live in Europe, in country Slovenia.
Is there anything worth trying to fix LTE speed in custom ROMs? I have the global version Pocophone F1.
Thanks in the advance for the help.
Click to expand...
Click to collapse
Brother, at the lineageOs is written that It enables a lot of new bands(LTE). Do you know if this is true ?

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I was having this issue in mind to talk about and good to see I'm not alone. I have tried hell lot of ROM, Kernels and almost all beta vendors+firmware combinations sometimes on recommendations of others as well. For example people say all 9.4.* ven+fw are bad for LTE speed.
I would like to know if you have tried latest Stable ven+fw for your existing custom ROM, this would not always match MIUI LTE speed, but will be close enough. Try this - https://mirror.akhilnarang.me/MIUI/beryllium/beryllium-V10.3.5.0.PEJMIXM-9.0-vendor-firmware.zip - specifically and update with a test results.
Also, LTE Discovery (a root app from Play Store) helps knowing in what cell tower you are connected to and if the behavior of speed depends on that. The strength of signal and direction of cell tower are to be noted.

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Mattewsb said:
Brother, at the lineageOs is written that It enables a lot of new bands(LTE). Do you know if this is true ?
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Click to collapse
I don't know if it is true, I'm not from USA, so I don't know whether unlocked bands work or not.
@vijay-in I have been using beryllium-9.6.3-9.0-vendor-firmware.zip. I also tried all different vendors, sadly no avail... I will try this vendor though I doubt it does any changes regarding LTE speed because LTE speed worked in MIUI regardless of vendor versions. Going to try that vendor you posted. And I'm using latest Havoc OS.
Edit: no changes. I'm using beryllium-V10.3.5.0.PEJMIXM-9.0-vendor-firmware.zip and nothing changed

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Karibes said:
Okay, give me a moment.
Edit: which tab do you wish to know?
Edit1: http://prntscr.com/o3jo0c (I hope that's one you were looking for...)
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Click to collapse
From the screenshot, the phone is connected to band 3/1800 Mhz frequency which offers less speeds. The values of RP/NR are also low which means you're in low coverage zone. In my country, this band max output speed is 18Mbps. I don't think you will get 50-70Mbps in this band anyway.
Here's an easier explanation of how this works:
Best coverage: Band 5 > Band 3 > Band 40.
Best speed: Band 40 > Band 3 > Band 5
Check atleast 1-2 times a day to see if it latches to B40 which would give you maximum speeds on LTE/4G. Every country has it's own bands so you have to check yourself which band your operator offers to you. The above example is from my country network operators.
In case you want to test why you get more speeds on miui, flash back miui and check which band the phone gets connected. There can be plenty of reasons for low speeds on custom roms, may be it's related to vendor, network issues, signal at that time, band connectivity etc. It's not easy to find out an answer as to why you get low speeds on custom roms but it's not like custom roms provide low speeds on lte, I'm getting same speeds on both custom and miui roms.

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Karibes said:
Hello,
firstly I apologize in the advance if there is a such thread made for this issue and if I opened the thread in the wrong location.
Now, regarding the issue is with the LTE speed between original MIUI and custom ROM. I have tried all custom ROMs: Lineage OS, Havoc OS, Nitrogen OS and Pixel Experience. All are working perfectly with one big downside and that is LTE speed. With MIUI I get full LTE speed about 50-70Mbps, HOWEVER with all custom ROMs I get LTE speed strictly limited to 4-5Mbps for unknown reason. I flashed different vendor firmware version, I even tried with root and without root. Sadly I got same results.
All I know that custom ROM is based on AOSP so I assume there is something missing something. I live in Europe, in country Slovenia.
Is there anything worth trying to fix LTE speed in custom ROMs? I have the global version Pocophone F1.
Thanks in the advance for the help.
Click to expand...
Click to collapse
Karibes said:
I don't know if it is true, I'm not from USA, so I don't know whether unlocked bands work or not.
@vijay-in I have been using beryllium-9.6.3-9.0-vendor-firmware.zip. I also tried all different vendors, sadly no avail... I will try this vendor though I doubt it does any changes regarding LTE speed because LTE speed worked in MIUI regardless of vendor versions. Going to try that vendor you posted. And I'm using latest Havoc OS.
Edit: no changes. I'm using beryllium-V10.3.5.0.PEJMIXM-9.0-vendor-firmware.zip and nothing changed
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Click to collapse
There's some applications that allows you to check bands that you are able to connect like network signal guru, give it a try and let me know, please

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Karibes said:
@vijay-in I have been using beryllium-9.6.3-9.0-vendor-firmware.zip. I also tried all different vendors, sadly no avail... I will try this vendor though I doubt it does any changes regarding LTE speed because LTE speed worked in MIUI regardless of vendor versions. Going to try that vendor you posted. And I'm using latest Havoc OS.
Edit: no changes. I'm using beryllium-V10.3.5.0.PEJMIXM-9.0-vendor-firmware.zip and nothing changed
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Click to collapse
I am using OxygenOS port from 6T beta, and the stable vendor has changed things regarding LTE certainly, I was getting maximum 10Mbit on Band40, but now it goes up to 30Mbit sometimes +.
I see you are in Band 3 (1800) coverage which has the worst bandwidth 5MHz instead of 20MHz (at some places 10MHz) of Band 40 (2300) and 10MHz of Band 5 (850). Ideally as mentioned in other comments, Band 3 should be faster than Band 5, but not in case of Jio at most places. The bandwidth is very less and Band 3 ensures you get pathetic speeds.
Try moving to the part of your house and find the spot where you get Band 40 (or Band 5) and try speedtest. I have identified some spots in my house where I get 30Mbit and when I have to download in GB, I get there and fire You can use LTE Discovery from Play Store as I mentioned in last post also.
Edit: No offence to anyone, but in my opinion locking band using Network Signal Guru may prove to be disastrous sometimes and you can be without network in some places when you need the most.

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Daruwalla said:
From the screenshot, the phone is connected to band 3/1800 Mhz frequency which offers less speeds. The values of RP/NR are also low which means you're in low coverage zone. In my country, this band max output speed is 18Mbps. I don't think you will get 50-70Mbps in this band anyway.
Here's an easier explanation of how this works:
Best coverage: Band 5 > Band 3 > Band 40.
Best speed: Band 40 > Band 3 > Band 5
Check atleast 1-2 times a day to see if it latches to B40 which would give you maximum speeds on LTE/4G. Every country has it's own bands so you have to check yourself which band your operator offers to you. The above example is from my country network operators.
In case you want to test why you get more speeds on miui, flash back miui and check which band the phone gets connected. There can be plenty of reasons for low speeds on custom roms, may be it's related to vendor, network issues, signal at that time, band connectivity etc. It's not easy to find out an answer as to why you get low speeds on custom roms but it's not like custom roms provide low speeds on lte, I'm getting same speeds on both custom and miui roms.
Click to expand...
Click to collapse
Mattewsb said:
There's some applications that allows you to check bands that you are able to connect like network signal guru, give it a try and let me know, please
Click to expand...
Click to collapse
vijay-in said:
I am using OxygenOS port from 6T beta, and the stable vendor has changed things regarding LTE certainly, I was getting maximum 10Mbit on Band40, but now it goes up to 30Mbit sometimes +.
I see you are in Band 3 (1800) coverage which has the worst bandwidth 5MHz instead of 20MHz (at some places 10MHz) of Band 40 (2300) and 10MHz of Band 5 (850). Ideally as mentioned in other comments, Band 3 should be faster than Band 5, but not in case of Jio at most places. The bandwidth is very less and Band 3 ensures you get pathetic speeds.
Try moving to the part of your house and find the spot where you get Band 40 (or Band 5) and try speedtest. I have identified some spots in my house where I get 30Mbit and when I have to download in GB, I get there and fire You can use LTE Discovery from Play Store as I mentioned in last post also.
Edit: No offence to anyone, but in my opinion locking band using Network Signal Guru may prove to be disastrous sometimes and you can be without network in some places when you need the most.
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Click to collapse
Okay, I flashed to original MIUI and sure enough, it is way weird.... http://prntscr.com/o42grn Here is the link of speed using Opera with LTE and right picture is taken from Network Guru. I don't see difference at all except LTE speed.... I'm seriously baffled... I probably can live with 600KB/s download using custom rom. Way weird bug or my phone is haunted to the hell...
Edit: I took this screenshot on same spot while testing the speed. Here where I'm sitting right now, I get full LTE speed on MIUI, on other hand with custom ROM, I get mere 600KB/s...

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Karibes said:
Okay, I flashed to original MIUI and sure enough, it is way weird.... http://prntscr.com/o42grn Here is the link of speed using Opera with LTE and right picture is taken from Network Guru. I don't see difference at all except LTE speed.... I'm seriously baffled... I probably can live with 600KB/s download using custom rom. Way weird bug or my phone is haunted to the hell...
Edit: I took this screenshot on same spot while testing the speed. Here where I'm sitting right now, I get full LTE speed on MIUI, on other hand with custom ROM, I get mere 600KB/s...
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Click to collapse
That's weird for sure If this is same with all custom roms, there is something wrong with either all of them or the stock MIUI
You have 20MHz bandwidth in Band 3 which is different from what we have here, so my previous answer was incorrect. So, you have a strong and fast Band 3. Probably it is the best in your country and has nothing to do with difference in results.
I am sorry that there is nothing much one can suggest, though I sincerely hope someone would help you with this. One thing you can try is, flash many popular custom roms over weekends and see if anyone can come near that speed, difference of this fold is quite unbelievable.

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vijay-in said:
That's weird for sure If this is same with all custom roms, there is something wrong with either all of them or the stock MIUI
You have 20MHz bandwidth in Band 3 which is different from what we have here, so my previous answer was incorrect. So, you have a strong and fast Band 3. Probably it is the best in your country and has nothing to do with difference in results.
I am sorry that there is nothing much one can suggest, though I sincerely hope someone would help you with this. One thing you can try is, flash many popular custom roms over weekends and see if anyone can come near that speed, difference of this fold is quite unbelievable.
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Click to collapse
Do you think there is something in AOSP because all custom ROMs are based on AOSP and (just loud thinking) I assume devs didn't add any files in AOSP or something for Europe to boost LTE speed? Though I'm not really sure but I know that MIUI has something that gives a full LTE speed while custom ROMs "restricting" LTE speed because in all custom ROM, I get 500-600KB/s, no more, no less... I'm sadly not a programmer/coder so I cannot investigate it myself...

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I see you have used multiple vendor+firmware beta/stable and have had same results, but I still think it is related to modem firmware, though I maybe absolutely wrong and it is not logical as well.
As you have nothing to loose, please try a really older firmware which is known for not having speed bug. Just firmware, not vendor.
Go to ip dev's GDrive https://drive.google.com/drive/folders/1zGc3v1ahsN2dpkPppNAJJMDHKl8jnQmj go to xfiles and download POCOF1Global_9.3.28-firm.zip (91MB)., this has only firmware which could be flashed in TWRP.
See if this helps. You can also try latest stock MIUI kernel from same gdrive - kernel-beryllium_global_V10.3.5.0-ak3.zip - on Custom ROM and see if that makes any changes.

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vijay-in said:
I see you have used multiple vendor+firmware beta/stable and have had same results, but I still think it is related to modem firmware, though I maybe absolutely wrong and it is not logical as well.
As you have nothing to loose, please try a really older firmware which is known for not having speed bug. Just firmware, not vendor.
Go to ip dev's GDrive https://drive.google.com/drive/folders/1zGc3v1ahsN2dpkPppNAJJMDHKl8jnQmj go to xfiles and download POCOF1Global_9.3.28-firm.zip (91MB)., this has only firmware which could be flashed in TWRP.
See if this helps. You can also try latest stock MIUI kernel from same gdrive - kernel-beryllium_global_V10.3.5.0-ak3.zip - on Custom ROM and see if that makes any changes.
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Click to collapse
I tested both and it became more weird again... xD Speed increased by mere 100KB/s but... Youtube app doesn't play at 1080p and it buffers way badly than on previous build... :/
May I ask how is the Oxygen OS? I would like to try it out as well.

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Karibes said:
I tested both and it became more weird again... xD Speed increased by mere 100KB/s but... Youtube app doesn't play at 1080p and it buffers way badly than on previous build... :/
May I ask how is the Oxygen OS? I would like to try it out as well.
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Click to collapse
Strange things happening with your LTE
Newer 7pro ports are kind of pre-alpha and have bugs. OOS 6T Beta 10 was the last in that branch of development, which I use as daily driver, it is best per my opinion after trying lots of roms, especially if you play games. You can definitely try it if it resolves your LTE issues.
The dev has taken down links, but I have it mirrored for myself http://dl.vj.lc/Poco-OOS/ Flash OOS zip only, it has vendor included. Test it that way.
Later on, update to newest vendor and flash vendor_patch.zip. Whenever you flash new vendor don't forget to flash vendor_patch. Latest is now 9.6.18.

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vijay-in said:
Strange things happening with your LTE
Newer 7pro ports are kind of pre-alpha and have bugs. OOS 6T Beta 10 was the last in that branch of development, which I use as daily driver, it is best per my opinion after trying lots of roms, especially if you play games. You can definitely try it if it resolves your LTE issues.
The dev has taken down links, but I have it mirrored for myself http://dl.vj.lc/Poco-OOS/ Flash OOS zip only, it has vendor included. Test it that way.
Later on, update to newest vendor and flash vendor_patch.zip. Whenever you flash new vendor don't forget to flash vendor_patch. Latest is now 9.6.18.
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Click to collapse
Thanks! I will try it right now. I will inform you shortly on how it goes :good:
Edit: why did he disable links? Just asking because I peeked and I saw latest version... quite odd...
Edit1: Okay, it is literally same thing with LTE... though Oxygen OS is very smooth and I quite like it but LTE speed... is quite severly limited... Maybe something is wrong with the my phone and I need to RMA it... I really don't know... Your Poco F1 works good... so why... :crying::crying: