Try doing this:Formatted SD-card to FAT32-format, copied update.app to dload folder, turned phone on while pressing volume up- and volume down buttons and waited till update was finished.
It's weird I know. Example, I moved all the apps to SD-card, took it off the phone, rebooted phone without SD-card and after reboot, apps were still there. This just doesn't make sense.
1) Place dload on internal sd card (HWUserData in root explorer)
2) Remove your sd card and battery
3) While pressing vol up, down and power button simultaneously connect data cable to your phone
If even this doesn't work, you'll have to restore a full flash of emmc I think, but it'll lead to loss of your IMEI, serial and MAC (they'll be changed to non-yours) so you'll lose warranty if any.
Hope I explained it right and sorry for my terrible English.