Update Huawei Ascend P7 L10 to Android 5.1.1 !

UDPATE: Because of certain issues with the initial article, I’ve researched the update process thoroughly and updated the article accordingly, to resolve the initial direct B830 update issues.

I was a bit tired of waiting for the stupid Android 5.1.1 (Lollipop) update to show up within the phone updater, so I’ve taken things into my own hands…

Here is what you need:

  • Huawei Ascend P7 (unbranded European P7-L10 only!) smartphone with fully charged battery
  • microSD card inserted in the phone
  • USB cable
  • 7-zip, WinRAR, PeaZip or other archiver capable of unpacking archives with updates

Plus the following updates:

Latest update:

You have to first have B839 installed on your phone before you can upgrade to B852. OTA updates are incrimental and they have to be installed in a correct order! B839 -> B852 !

This update ONLY supports following existing builds:

P7-L10V100R001C00BXXX
P7-L10V100R001C900BXXX

Check Settings -> About Phone -> Build number if numbers match. In my case, the first one was a match, the XXX can be any number, it was 135 in my case followed by SP04. But I don’t think that’s important. BXXX numbers however are very important!

If they don’t match, anything you do in advance is on your own risk! I recommend you don’t update it if the version numbers don’t match.

Updating process for versions lower than B621

I recommend wiping the phone prior updating to avoid potential issues. Backup your internal data and transfer/deactivate your Google Authenticator codes before you perform factory reset!

  1. Download B621 firmware, unpack archive and copy entire dload folder to your Ascend P7 microSD card root using USB cable.
  2. Turn off your phone. Wait for it to fully shut down.
  3. Press VolumeUp+Power buttons and release them when logo appears on screen.
  4. Select Wipe Cache partition and then Wipe data/factory reset.
  5. Restart the phone and skip all the first start settings.
  6. Shut down the phone.
  7. Press VolumeUp+VolumeDown+Power buttons until the phone starts. This will force install B621 update.
  8. Download B621 CUST Hotfix, unpack it and copy entire dload folder to microSD card. This will replace old update files (confirm overwriting the files).
  9. Shut down the phone.
  10. Press VolumeUp+VolumeDown+Power buttons until the phone starts. This will force install B621 CUST Hotfix update.
  11. Download B830, unpack it and copy entire dload folder to microSD card. This will replace old update files (confirm overwriting the files).
  12. Shut down the phone.
  13. Press VolumeUp+VolumeDown+Power buttons until the phone starts. This will force install B830 update.
  14. Download B839, unpack it and copy entire dload folder to microSD card. This will replace old update files (confirm overwriting the files).
  15. Shut down the phone.
  16. Press VolumeUp+VolumeDown+Power buttons until the phone starts. This will force install B839 update.
  17. DONE!
  18. Setup your phone by adding Google Account or simply factory reset it again for first start setup wizard to appear.

It looks complicated, but after step 7, it’s basically a repeating task for each build.

Updating process if you are running a version B609 or newer

If you’re using B609 or later (because your phone arrived with it when new or it updated itself to this version), you should be fine updating directly to B839, but you strictly have to use a full version update which is around 1,5 GB in size (the above link).

Updating process if you have already updated directly to B830 or B839 and you’re experiencing functionality problems

If you have upgraded from lets say B135 directly to B830 or B839, like I have, you have most likely experienced several issues after doing factory reset. Missing keyboard, lockscreen and wallpaper images locked together, missing Motion Control settings etc. In this case you have to first downgarde your phone back to B621. You have to use the same chain of upgrades, just in reverse to downgrade your phone. I had B839 installed, so I had to first downgrade it to B830 and then B621. Made a factory reset and then repeated the above B621 updating process, step by step. Updater may say that firmware upgrade failed in the very end of each downgrade, but don’t worry, it will work anyway. You can check your build version number on each downgrade step if you want to be sure. Going back from B621 to B839 should not show any more FAILED messages. It should successfully update them.

Why all these problems appear?

Apparently the CUST issues happen when manually transitioning from Huawei’s EMUI 2.x custom interface to latest versions that use EMUI 3.x. It somehow conflicts. But if it’s already running EMUI 3.x, there should be no problems updating directly to latest version.

Synopsis

Everything is working perfectly now, no issues, no missing features, just the latest OS and super smooth functionality. From now on, you should receive updates through integrated updater or by new builds (I might update the article with that in the future). Android 6.0 (Marshmallow) is allegedly also planned even for Ascend P7, so it might be interesting. We’ll see…

Enjoy!

PS: If you need any extra info, ask me down below and I’ll check it out for you.

142 thoughts on “Update Huawei Ascend P7 L10 to Android 5.1.1 !

    1. Well, I recommend factory resetting the phone before updating, however, these updates are designed to retain user data. Meaning, if you have a version lower than B621, you can upgrade it step by step described in my guide without doing a factory reset first and all data will remain. I’m not sure if the same will happen when you’re downgrading though… It’s more problem free for sure if you start from clean, but if you can’t, just try updating without factory reset.

      Like

  1. thank you man, everything’s explained perfectly.
    i had an ascend p7-l10 branded, with android 4.4.2
    now it works with 5.1.1,

    thanks from Italy again

    Like

  2. One question, if I have B623 do I need to downgrade to B621 or I can go directly to B830 then B839?
    Thank you very much!

    Like

    1. If you’ll go directly you’ll experience various pretty big problems. I mean, the phone will work, but you’ll be missing keyboard, motion control settings, lock screen will be locked down, you wont’ be able to selct separate images for lockscreen and wallpaper, you won’t be able to use themes.

      I’ve asked on XDA if there is any B623 CUST “hotfix”, but I think you’ll have to downgrade to B621 first, because the CUST hotfix only exists for B621 at this moment.

      Like

      1. Can you send a message to me?I need ” P7-L10 B621 CUST Hotfix”….my email is “hqw825146572@hotmail.com thanks for you…

        Like

      2. Just use the link above. I suggest you switch OneDrive list display to “Detailed” instead of “Tiles” so you’ll see it easier.

        Like

    2. Apparently, the issues only appear when transitioning from EMUI 2.x (pre-B621) to EMUI 3.x. B623 is already running EMUI 3.x interface so you should be fine updating directly to B839 (but you have to use a full version update).

      Like

      1. What do you mean by a “full version update” ? B830 andB839 that are here are not full versions?

        Like

      2. All updates listed on my page are full. I just specifically pointed it out so people won’t update to B839 using OTA package or something.

        Like

    1. B619 is already EMUI 3.0 as far as I know. I think you can just update directly to B839 (full version). Those problems only happen when updating from EMUI 2.x to EMUI 3.x. But I can’t be 100% sure since I haven’t tested that myself (since I was on different starting build). If you’re willing to try it out and report back, I can update the guide with credits for your help.

      Like

    1. It’s normal for phone to boot into the updater. When does it say “FAILED”? Right away or at around 20%? What is your full ROM build already installed on your phone?

      Like

      1. Well , thanks for fast replay .. the problem was from the MicroSD card , i changed it and it works will , my mobile was build of B619 with EMUI 3 , as you said at top ” B619 is already EMUI 3.0 as far as I know. I think you can just update directly to B839 ” i didnt want to skip it to avoid gettin problem so i highly recommand thats even if your build is B619 to upgrade B621 then go for B830

        Like

  3. i’m on B609 with CUST432D609, can i go B621->B830->B839, or B621->B621 cust fix->B830->B839?
    Everything works on this rom?
    I use snapchat is that working correctly?
    This is my primary phone.

    Now i have seen THIS can i update from B609 to B839 directly ?

    Like

  4. Hello,
    I updated from B136 directly to B839 and then via local update to B852.
    Several problems like missing Motion Control and more.
    I tried to downgrade from B852 to B839 and B800, both failed in the very beginning of the Upgradeprocedure.
    I also tried the transitionpack from Huawei to get EMUI3.0, B830, also not possible.
    This failed at 95% with Huawei CUST FAIL, post_update_fail.
    Any suggestions?

    Like

    1. Try downgrading directly to B621. If it fails, factory reset phone again and then force flash it with B621 again. I just kept trying until all of a sudden it just magically (for no real reason) updated the damn thing. It’s so weird all this shit is happening in the first place. I’ve never seen such bizarre problems with official updates on any other device. Though Huawei is rather unique with option to flash updates like this. For example, Samsung doesn’t even offer such updating. At leat I’m not aware of it and i had several Samsung phones.

      Like

  5. It updated with B621 to 100% and then again the CUST_FAIL message
    but it started with B621!!!!!!!!
    And now factory reset and installing the CUST-Fix?

    Like

  6. No matter, that’s fine. If you have B621 installed you’re on the right path! Now install the CUST fix. It should install without an error. After that, all future updates will install 100% without any errors or failing. At least that was in my case. Most crucial is to get B621 running and installing that CUST fix. Once you install it, the update errors/failed are gone.

    Like

    1. That’s correct. It’s just a fix for a very tiny configuration file(s) that fucks all up if it’s missing. That’s why it’s so critical to install this thingie.

      Like

  7. Hurrayyy, working, and the Motioncontrol-Settings are visible and also the CUST-Version.
    Great!!!!!
    Is it possible to upgrade now directly to B839 with the B839Fullversion?

    Like

    1. I’d skip it and manually update directly to latest versions. It’ll be faster than waiting for all the itterations to come up for you through updater. Unless if you don’t mind waiting.

      Like

  8. Ok, manual Update to B839 and after restart it offers me Update to B852, everything works fine at the moment.
    Thank you so much for helping me.
    Have a good time and a happy new year 2016

    Like

  9. After updating my touch screen don’t work sometimes and i have to restart my phone or lock/unlock to fix that. I haven’t noticed that on B609 (maybe), what i should do? Should i go to servis maybe?

    Like

  10. I upgraded it manually from B132 to B621. The process was 132-133SP01-609-621. It stayed like this for a day, and didn’t have any problems. However after reading this I upgraded it with the CUST fix which did a factory reset and that surprised me. Non of the updates did a factory reset, but this fix did. So, what I am asking is, what this CUST actually does, beside the factory reset? Was it worth it? I had no problems before.

    Like

    1. No, CUST fix doesn’t just reset the phone. It contains custom firmware specifications. If they are missing, weird things happen, like missing Motion control etc. I don’t know what exactly it does, but I know it does something and that it works. And it has to be from Huawei, because you can’t just flash random stuff, it has to be signed by Huawei. Meaning this had to arrive from Huawei directly.

      I probably just didn’t notice it resets the phone because I was working on a clean phone so there wasn’t any difference anyway.

      Like

      1. I don’t know what problems, B852 works great. Only complaints I’ve seen so far were all related to missing features which happened because of broken CUST.

        Dunno, only problem I have is Twitter app not opening webpages within Twitter app even though I have that set in the app itself. It always tries to open links in external browser. But other than that, no other issues. And I think it’s Twitter fault anyway.

        Like

  11. Thanks for this great tutorial. I update my p7-l10 following step by step your instructions from 1. to 18. (even i was on B609). It works great so far !!!!!!!

    Like

  12. I upgraded my set to B839 now keyboard is missing and in start process for installing the update the message was the this phone is secureboot. Can you help me to restore my keyboard.

    Like

    1. To me kit seems more like a CUST problem, similar one I was facing when I updated phone directly from B135 to B839. I’ve exprienced similar issue when I’ve upgraded to Asian version of B853. Less things were broken, but they were broken.

      Like

  13. Thank you very much for this great tutorial. I update my p7-l10 following step by step your instructions from 1. to 18. (even i was on B609). It works great so far !!

    Like

    1. You can install B839 directly and then OTA B852 update, because you’re already on the Lollipop / EMUI 3.x branch. There is still no full B852 available so this is the only way for now.

      Liked by 1 person

    2. okay so i readed the article all over again.. with B815 what is the first thing to do? should i downgrade it to b621 to apply the CUST fix or is it ok to just update to b830?

      thank you!

      Like

      1. To my knowledge and research, CUST fix is only needed when upgrading from old B135 builds (Kitkat) to latest ones like B839 (Lollipop) directly. Downgrading is only needed when you fuck up with direct updating from B135 to B839 without using CUST fix in between. In your case, you’re already on Lollipop, just some older build. It should go fine directly. If you’ll experience problems like I have, then just follow the downgrading process and use the CUST fix. There is no way knowing what will happen for sure, because there are so many scenarios and this one in particular is the one I haven’t tried myself so I could be wrong. Please don’t kill me if your phone explodes or something afterwards 😀

        Like

    1. Exploding thing yes, something maybe going wrong, not so much. Huawei seems to have tons of different custom configurations for their ROM’s. There is a chance that it might conflict with your specific device. In my case the conflict was in transition between B135 and B830/B938 because of huge differences in versions. You’re already on Lollipop build so so chances for something breaking down are a lot smaller. But like with anything else, it can happen.

      I just checked, B815 was European Lollipop BETA build. i think you’ll be fine updating directly to B839.

      Like

      1. Okay so I did the update and BOOM!! nah jk.. Awesome help, my phone is faster, battery drain almost gone (still consumes a bit fast on 3g, wi-fi all good) facebook videos are working as well as instagram ones, apps not blocking, system buttons don’t disappear anymore, stable RAM, sound improved, no more freezed screen which means you won’t have to reboot your phone 45296 times a day!

        Awesome, thank you very much

        Like

      2. Go to settings and check if “Motion control” is working. Also go to “Language & Input” and check if Huawei for Swype is still listed there. If Motion control isn’t working or if Huawei for Swype is missing, then something is wrong. If all this works fine, then it was most likely a successful update.

        Like

  14. Hello,
    I have problem with viber video calls … Firmware version B852, …. When I try to make viber video calls my screen goes black… Anyone with same problem and with any solution….
    Thanks

    Like

  15. Hi,
    Need your help. Hope you can rescue my P7 L10 (V5.1.1)
    Recently i got B852 OTA update notification. I tried to update but during the update, it
    went into a black muted screen for hours. So, i have to manually reboot my phone. And of course the firmware updated failed!

    I googled around and found out about extracting .img files and flashing using adb tool.
    – So, i extracted boot.img and recovery.img from the one (dumb enough that i didn’t check.) i downloaded from somewhere from the web.
    – And i was able to flash them via adb tool in fastboot mode.
    – After successfully flashing them, the phone wakes up in EMUI screen. Picture link [http://www.hard-reset.com/images/huawei_p8_lite_hard_reset.jpg]
    – From that onward whenever i reboot the phone, it will always wake up on that screen.
    – When i charge the phone, it will awake and keep staying on Huawei Ascend logo splash screen.

    Any thoughts?

    Thanks in advance,

    Like

  16. The update worked perfectly. But the last update (B852) had a few quirks. Firstly, it doesn’t unzip like the rest. a few folders and no dload folder. Even when i use put the UPDATE.APP into a dload folder it doesn’t work. Unless there is something i’m doing wrong. The rest work perfectly.

    Like

  17. I had b619 version and directly flashed B839. During the process I got “failed” message however when phone was rebooted it was upgraded to 5.1.1. Dont know how it is done. so far its working OK.

    Like

  18. hello sir i have ascend p7 l10 ,purchase from kuwait now i am in pakistan ,update shows i updated my phone and now its on b619 emui 3, i dont knows what is the oldest firmware.
    i want to rollback that verision ,how i do it???? plz tell me and one thing more that if i want to go lollipop ,whats step i did on my phone……

    Like

  19. I did all the steps, from this guide but just till the b830.. I have the keyboard and that stuff but I still have problems with the apps, facebook, snapchat and whatsapp crashes all the time and I’m desperate, I like to have the lollipop version because that way I can have all the sanpchat features but it is really annoying to see all the applications crashing. Do you think upgrading to de B839 can fix that problem ?

    Like

  20. Thank you very much for your help and support your post really saved me
    i got B619 then i move directly to B839 i got an issues in keyboard and motion control etc
    i follow your post is the correct order now i got B852 without any errors till now.
    Thanks Again :D.

    Like

    1. if you have read this article says clearly that you can do it !!!It’s up to you. I had B609 but i fillow all the steps here until B852 and now my phone works perfectly

      Like

  21. huawei p7-L-10, build number p7-L10v100r001c00b619 buy in kuwait.
    how u can update my phone….pls help me!

    Like

  22. huawei p7-L-10, build number p7-L10v100r001c00b619 buy in kuwait.
    how u can update my phone….pls help me! n suggest me..fast…

    Like

  23. Hey i upgraded straight from old version of kitkat 135 to latest b852…not motion control missung and a few other stuff.what method can i use to correct this…straight tp b621 then b852?

    Like

  24. Thank you for this tutorial.. i just upgraded from b126 to b621 and cust hotfix.. im still downloading b830.. anyway i just want to add, if you dont have a micro sd card, just copy the dload folder on the root of your phone storage.. and to make things simple, just hit the updater in settings and update local.. it will automatically locate your update.app file and start to update your phone, no need to power off and press buttons(power+vol up+vol down).

    Like

  25. have finish this tutorial, and got b839 firmware, i want upgrade to b852 but confused with ota upgrade, i found article ( link: http://bit.ly/1ULZPqm ) about b852 full firmware and ota upgrade, what do you prefer with this firmware, full rom update or ota update.

    Like

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