[Huawei Mate 9 Guides, News, & Discussion] Jlew3501:
Successfully Downgraded from B125 to B109 on 64GB Mate 9

Hi Everyone,

With the help of duraaraa I was able to successfully downgrade from B125 to B109. We had to try multiple times and through the process of elimination we found a way. I have the 4GB/64GB version. I will detail what we've done but I cannot guarantee this will work for everyone.

With the phone not plugged in, I factory restored the phone (B125) from the settings menu. Once it booted up I went through the start up wizard and skipped everything and kept everything of,f all Huawei services and did not add any fingerprints. I then went into the fingerprint menu and added two finger prints (since that's how many I had before the restore) and removed them. Next "factory data reset" the phone. When the phone turns off DO NOT let it boot, the moment it turns off hold the volume up (+) button until you see the recovery screen. Then select wipe everything and wipe the cache, options 2 and 3. Do not restart the phone yet.

Change your router DNS settings, test it and make sure it works with another phone/pc. Once your DNS settings work plug in your phone to a computer or charger (I used a portable battery for all of this). Restart the phone and hold the volume up button like before, you will now be taken to the eRecovery option to download a recovery. You should first be prompt to connect to your wireless network, if you don't see this it means you did not clear the cache. Once connected it should be downloading the B106 firmware which is about 2.4GBs. It took me about one and half hours to download. Once it reaches 95%+ keep an eye on the phone. When it finishes downloading it will auto install and when complete it will auto reboot, it will countdown from 10 seconds or you can hit the reboot button. This is extremely important, DO NOT let it boot the B106 firmware.

IF you miss it and it boots the B106 firmware it will bootloop, you will need to restore your DNS, recovery to B125 and start again. I had to do this a few times and it takes forever.

When the phone reboots, the moment the screen turns off I hold the volume up button to go back into eRecovery. The phone is plugged in the entire time. Once you go back to recovery you can download the recovery file, this time it should be the B109 firmware at 274mb. Once it downloads it will auto install and reboot. For some reason when it install the B106 firmware it tried to download the B106 firmware again. All I did was canceled and turned off the phone, unplugged the phone and booted into eRecovery to factory wipe and wipe cache. Plugged it back in and boot into recovery and it started to download B109.

If for some reason your phone bootloops after installing B109 unplug your phone, boot into recovery via holding the volume up button. Wipe everything AND the cache. Your phone should now boot properly and be able to see the EMUI start up wizard.

Once you set up your phone, download the Play Store from the Huawei app and you should be good to go. Enable developer settings and disable auto updates then change your DNS to its default setting.

Special thanks to duraaraa as we spent a lot of time figuring this out.

Some pictures. I am a new user so I cannot post links:

ht tp://imgur.com/jDLiV99

ht tp://imgur.com/k2BvfFL

ht tp://imgur.com/3KkQoNJ

If you have any questions that duraaraa is unable to help you with you can PM me. I am probably not going to monitor this thread. Keep in mind I have zero technical background and am just a customer who purchased the Chinese Mate 9 and searched online for a solution. I am currently on vacation as well so please do not expect an instant reply.

Again thank you so much duraaraa for helping me.

Good luck everyone.