His phone keeps restarting whenever I turn the wifi on and there is no phone signal. I mean visually the signal bar is there but no calling or checking credit balance could be done.
This happened since he did software update from sony's end to R800i_4.0.2.A.0.42.
Upon lurking xda, I found out these problems may be caused by the baseband.
Therefore I used flashtool to flash:
>and one other custom rom called GB something
I also tried to flash new kernel:
note: I wanted to try doomkernel but I couldnt find working download link
Other than that, I tried to flash only the baseband:
However, I couldn't solve the problems with the previous steps. I need advice from experienced users, thank you guys..