Hi!
I've been trying to update my Huawei W1-U00 to WP 8.1 Update 2 for some time now, but it seemed to be impossible. Yesterday I finally found the way to do it, and I wanted to share this info with you guys.
1. You need to install custom ROM by WojtasXda v1.32
http://forum.xda-developers.com/showthread.php?t=2686053
2. Install Preview for Developers, activate it and then install all the updates you can
3. Install registry editor to your phone and change these keys this way:
[HKLM\SYSTEM\Platform\DeviceTargetingInfo]
"PhoneManufacturer" = "ARCHOS"
"PhoneMobileOperatorName" = "000-88"
"PhoneManufacturerModelName" = "BUSHWindowsPhone"
4. Deactivate Preview for Developers and search for updates again
5. Install the updates and that's it. Now you have WP 8.1 Update 2 on your phone!
Other tips:
After step 5 is done, you can use registry editor to change the keys back as they were before
If you want to install some apps made for Lumia Phones only, like Lumia Camera or PhotoBeamer, you first need to set these values:
[HKLM\SYSTEM\Platform\DeviceTargetingInfo]
"PhoneManufacturer"="NOKIA"
"PhoneManufacturerModelName"="RM-976_1115"
"PhoneFirmwareRevision"="01061.00066.14235.36003"
"PhoneHardwareVariant"="RM-976"
"PhoneMobileOperatorName"="000-GB"
That's it, I hope this helped!