[Huawei P8 Questions & Answers] BaneMaksin:
Enabling dual sim on devices with build 133

I have also struggled on how to enable the dual sim functionality on my Telenor branded device with build 133. So this is a short guide on how to enable it finally with (in)famous 133 firmware:

Unlock the device bootloader by following instructions from this video - https://www.youtube.com/watch?v=63L7FBuWFrc

Then root the device - https://www.youtube.com/watch?v=duquOuRqYDM (probably we don't need to do this, but it can came in handy to remove some Huawei apps later)

Since we can't do the "normal" firmware flash back to version 46, we will use fastboot to flash it. First download the latest Huawei update extractor from this post http://xdaforums.com/showthread.php?t=2433454 and extract it somewhere.

Then download the OP mega archive from the first post and unpack it also.

Then for proper fastboot flashing we are only missing the latest ADB and fastboot minimal install that can be downloaded here - http://xdaforums.com/showthread.php?t=2317790 and install it (the fastboot version from previously downloaded files are very old and don't work properly).

After we have downloaded and extracted all files, open Huawei update extractor and load the UPDATE.APP from OP step1 folder in it (field name "Update file").

When the file have been loaded into the Huawei extractor, the list of *.img files will appear. For our build 46 firmware flash we need bare minimum, so select BOOT.img, CUST.img, RECOVERY.img and SYSTEM.img. When those files are selected, right click on one of them and select "Extract selected". Choose the folder where have you previously installed minimal ADB and fastboot (by default on windows 7/10 it should be "C:\Program Files (x86)\Minimal ADB and Fastboot"). Now we are ready for some fastboot flashing.

Connect Huawei P8 lite via USB cable and check if developer mode is still enabled in settings. Navigate to the minimal ADB and fastboot install folder, hold shift + right mouse click and select "Open command window here". Then type in console window:

adb reboot-bootloader

This will boot your Huawei into the bootloader mode. Now in the same console type:

fastboot devices

If device was recognized, it should appear in the list. Now execute the following commands in window console:

fastboot flash system SYSTEM.img

fastboot flash recovery RECOVERY.img

fastboot flash boot BOOT.img

fastboot flash cust CUST.img

If every command were executed successfully, the device should now have firmware build 46.

Reboot the device in normal mode by typing in the console:

fastboot reboot

It'll start booting normally and start optimizing installed applications before entering the home screen. At this point we have successfully downgraded the firmware and can finally proceed to step2 from OP tutorial.

Copy the content of step2 folder to root of the SD card and go to "Settings -> Updater -> Menu -> Local update". Select the update and let it reboot the device. It should apply the update without any problems now. To be sure, check the build number in "Settings -> About phone" and also check if desired "Dual card management" menu is now available in the settings.

After everything, the last step is to upgrade from build 46 to build 132. Download the firmware from http://huaweidevices.ru/5huaweiromofficealfirmware3d/ALE-L211/Huawei_P8_Lite_ALE-L21_V100R001C432B132_Europe_Dual.rar and do the regular local update via SD card (move the dload folder into the root of SD card and from device initiate the upgrade process "Settings -> Updater -> Menu -> Local update").

If upgrade finish without any problem, you should have now fully functional Huawei P8 lite with dual sim support and latest firmware build 132.

Here is the screen shot from the device: