Hi, I've just done the Upgrade today and so far everything seems to be working OK. I had a problem getting the phone into Upgrade Mode. Every time I tried it would go into Pink screen so in the end I took out the SIM card and did a Format on the SD card.
I then loaded the card again and tried again - Pink screen!
I removed the battery and connected the phone by USB cable to PC and did the Vol+ Vol- Power button and it started the Upgrade.
I disconnected Safely from PC when Upgrade was finished - re-installed battery and Powered up the phone. I left the phone to settle down for a couple of minutes and then did the Set up.
All OK as I said Wifi / Networks / Bluetooth / GPS all working OK. I'm very pleased with Gingerbread 2.3.5 U8800V100R001C00B526G001 Upgrade.
In reply to your problem, have you tried re-installing again?
I actually wondered whether you might have a corrupt version.
This is where I got my Download from: HUAWEI U8800 - Huawei Device Co., Ltd..
Went into Software and got the Upgrade that I used. Cheers Neil.