Ok this is the last time I'll explain. In the rar file for SE-B there is a directory called 'flasher for recovery'. Inside the 'flasher for recovery' directory is a folder named 'RECOVERY'. Copy the folder named 'RECOVERY' over to your PSP\GAME folder on your psp's memory stick. Now you need to obtain a 1.50 update eboot. Rename the 1.50 update eboot to 'update.pbp' and copy it over to the PSP\GAME\RECOVERY folder on your memory stick. Now turn off your psp then turn it back on while holding down the 'R button'. You will enter the recovery menu and there is an option that says 'Run program at /PSP/GAME/RECOVERY/EBOOT.PBP' select that option then follow the onscreen instructions to flash back down to 1.50.