Your best bet is upgrading to official 3.73...since Dark_Alex has stated that the firmware 3.73 DOES NOT need any patch to upgrade to a custom firmware higher than 3.73 (that should be 3.80, to be released Dec. 18).
I thought by having an OFFICIAL SONY Firmware 3.73 all I needed to do was download a custom firmware (3.90 M33) and put the eboot file in the PSP/GAME/UPDATE folder.
Quote:I thought by having an OFFICIAL SONY Firmware 3.73 all I needed to do was download a custom firmware (3.90 M33) and put the eboot file in the PSP/GAME/UPDATE folder.
No, Unfortunately the process for installing custom firmware is much more complicated that what you tried to do. Trust me we all wish it were that easy ;)
Either way, in order to install 3.90 M33 or whatever version, from 3.73 Sony firmware, you will need to have a *hard modded Pandora battery* as well as a magic memory stick.
Once you have downloaded the total newbie eays installer. run the application and do exactly what it says.
After you have created both the Pandora battery and the magic memory stick, insert the stick into the psp. Than insert the battery. Then press X to install. What I just told you was a very quick guide on how to downgrade/install custom firmware, there are also alto of other guides at the top of this forum that are extremely easy to follow. However, try using the total newbie easy install first as i find it to be the easiest for beginners