I downloaded Universal 3 and install it on my working 3.40oe.
Followed all the steps and reached the black installation screen which ask me to dump nand or install 3.71 M33. I press X and install 3.71 M33 (sadly I didn't do a nand dump). The installation was successful but when I reboot the PSP, the black installation screen came back again.
Can anyone help me? Thanks.
-= Double Post =-
One more thing...I couldn't go back to recovery mode either...