Resolved Widevine L3 without any flash


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floone

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14 Feb 2021
18
15
My phone: Mi 9t (davinci)

Hi,
I was on EU Stable 12.1.2 with Widevine L1. A few days ago (I don't know exactly when it happend) it switched to L3 so I can`t watch Netflix in Full HD anymore.
I tried installing newest weekly but still L3. I tried installing the Widevine L1 patch by @Poney70 but it didn't solve it too. I don't know what happend that I only have L3. As I said I didn't do anything like wiping persist partion.
I read somewhere else that it is possible to flash the official global fastboot rom with Mi Flash. But I'm not sure whether I should do it. I don't want to destroy my phone more. Do you have any experience with this?
Moreover I have an nandroid backup of Eu Stable 12.1.2 (29.03.2021). Should I flash this?

Thank you
 
I tried everything now. Nothing solved the problem. even going back to official android 10 rom did not solve it
 
Same problem here, was using the stable ROM and out of the blue I lost Widevine L1, without changing anything...
 
Same problem here, was using the stable ROM and out of the blue I lost Widevine L1, without changing anything...
Sounds like the Widevine L1 key got expired or something. How did you check which Widevine level you have?
 
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How do you check Widevine level?
Use "DRM info" app..
 
36186
IMG_20210422_101213.jpg
 
Sounds like the Widevine L1 key got expired or something. How did you check which Widevine level you have?

I also used DRM Info, my Widevine CDM part looks exactly like the screenshot from @mar_robHD above. Just to make sure I also checked the picture quality in Prime Video/Disney+ and it's definitely not 1080p anymore.
If the key really expired, is there hope to regain it somehow?

Edit: To add, I had some time yesterday and tried all the different Xiaomi.eu ROM versions (Android 11 Stable, Android 11 Weekly, Android 10 Stable) with a data format and all still showed Widevine L3. I also backed up my persist and persistbak just in case, but a corrupted persist shouldn't be the issue since everything else still works, right?
 
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I also used DRM Info, my Widevine CDM part looks exactly like the screenshot from @mar_robHD above. Just to make sure I also checked the picture quality in Prime Video/Disney+ and it's definitely not 1080p anymore.
If the key really expired, is there hope to regain it somehow?

Edit: To add, I had some time yesterday and tried all the different Xiaomi.eu ROM versions (Android 11 Stable, Android 11 Weekly, Android 10 Stable) with a data format and all still showed Widevine L3. I also backed up my persist and persistbak just in case, but a corrupted persist shouldn't be the issue since everything else still works, right?
Stock ROM with "clean all and lock" doesn't work either. To corrupted persist: If I understand correctly, the sensors should also be faulty or no longer work if persist is damaged. Since they probably work for you (at least they do for me) the persist partition should work
 
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Stock ROM with "clean all and lock" doesn't work either. To corrupted persist: If I understand correctly, the sensors should also be faulty or no longer work if persist is damaged. Since they probably work for you (at least they do for me) the persist partition should work
Ok, to try out stock ROM + relock Bootloader would have been my last resort, thanks for testing that (sucks that it doesn't work). Yes, from my limited knowledge I would also rule out a corrupted persist partition since everything else works fine.
But since Widevine L1 is gone regardless of the ROM, it needs to be related to our phones somehow. Also strange that it happened to multiple users at roughly the same time...
 
Ok, to try out stock ROM + relock Bootloader would have been my last resort, thanks for testing that (sucks that it doesn't work). Yes, from my limited knowledge I would also rule out a corrupted persist partition since everything else works fine.
But since Widevine L1 is gone regardless of the ROM, it needs to be related to our phones somehow. Also strange that it happened to multiple users at roughly the same time...
My phone dealer told me I could send it to Xiaomi under warranty. I'm not sure if they will really repair the software for free but it looks like that. You could try it too. I can send you the screenshot of the locked bootloader (they probably wanna se it) if your language is german (otherwise it's suspicious). So you don't have to flash Stock ROM again just for 1 screenshot (as I did).
However I'm not sure whether it makes any sense because I really enjoy xiaomi.eu ROM more than Stock. When I have L1 back I will flash back to xiaomi.eu and L3 could come again.... i dont know if it's worth it

By the way: Is it possible that Google did some updates on their security levels? Maybe they check if a device has original software and if not they block widevine L1. Could be possible because Google is the only one who updates their software on Android without any restart or any information for user.
 
Thanks for your offer, maybe I'll come back to that (I'm also german but I ordered the phone over a year ago from china, not sure if I even have warranty).

The Google theory could be true, but surely there would be more people (apart from a few Mi 9T users) who would have lost their Widevine L1? To be honest I don't know much about the ins and outs of Android and Widevine, so I can only guess.

@Igor Eisberg @ingbrzy (I hope it is ok to ping you): Is there anything more we can do/provide you with to get to the root of the problem?
 
It also could be something with the widevine keys xiaomi is using on the mi 9. Maybe the key is expired.

It also would be interesting, if someone owns a mi 9 with a working Widevine L1 security level. But I'm sure, that is definitely not Xiaomi.eu's fault.
 
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Or in settings > biometrics & security > fingerprint > fingerprint payments

Sent from my M2007J3SG using Tapatalk
On Mi 9t there's no widevine in fingerprint. I think it's because Mi 9t don't support OTA keys
 
@Igor Eisberg @ingbrzy (I hope it is ok to ping you): Is there anything more we can do/provide you with to get to the root of the problem?
We have no idea how Widevine keys work. It's well-encrypted for a good reason...

It also could be something with the widevine keys xiaomi is using on the mi 9. Maybe the key is expired.
That's my suspicion as well.

Or in settings > biometrics & security > fingerprint > fingerprint payments

Sent from my M2007J3SG using Tapatalk
Those who have "Widevine (L1)" in Fingerprint payments should be able to request a new key via OTA, so not an issue.

On Mi 9t there's no widevine in fingerprint. I think it's because Mi 9t don't support OTA keys
Correct.
 
Those who had L1 recently and it suddenly changed to L3, we need something from you.
1) Go to TWRP.
2) Connect the device to your PC, make sure you have ADB executable.
3) Run this commands:
Code:
adb shell
dd if=/dev/block/by-name/persist of=/sdcard/persist.img
4) Copy persist.img to your PC.
5) Send me the persist.img file somehow in private (this partition may contain some device-specific sensitive information, so don't go sharing it with people)

Let's see if you still have L1 key in there.
 
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Hello, update.
I have found that my second phone(also an Mi 9) still has Widevine L1. The mi9 is on 21.2.24
 
If there's no widevine l1 key in file from the phone with L3, there might be one in the file on the phone with L1
Yeah, and each key is unique and specific to the device it was generated for, they are not transferable.
The more persist partitions we analyze, the more we can learn.
 
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Those who had L1 recently and it suddenly changed to L3, we need something from you.
1) Go to TWRP.
2) Connect the device to your PC, make sure you have ADB executable.
3) Run this commands:
Code:
adb shell
dd if=/dev/block/by-name/persist of=/sdcard/persist.img
4) Copy persist.img to your PC.
5) Send me the persist.img file somehow in private (this partition may contain some device-specific sensitive information, so don't go sharing it with people)

Let's see if you still have L1 key in there.
I just sent you a PM with my persist.img, thanks for taking the time to analyze it! :)
 
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