EDIT: I FORGOT TO MENTION that your memory stick MUST be a genuine Sony stick for Despertar to work. if you don't have one, find one! also, it can't be higher than 4 GB. and always have your charger handy.
You won't be able to uninstall 5.00 again unless oyu have backed it up using Hellcat's.
The Flashing doesn't work correctly when installing a fresh M33 running on GEN-B.
Your only option is to aquire a pandora's battery, and use Despertat Del Cementario to downgrade.
You can use your own battery, you don't need to worry about having a backup.
First off, you need to back up your memory stick.
then DL
this.
use the "mspformat.exe" in that archive to format your memory stick.
turn off/get rid of any custom themes on your PSP.
copy the DC8 folder to the root/PSP/GAME folder of your memory stick (create folders in neccessary).
download the sony official eboot (I don't know if I can post it here, so I won't) for 5.00, easy to find.
rename it to 500.pbp (if neccessary), and copy it to your root.
run DC8 on your psp (it should have a tree icon thing) and follow the onscreen instructions.
afterwards, download Hellcat's Pandora Installer
here.
that's good, you now have your Pandora battery.
next, close the program, and go back to the XMB. pop the battery out, along with the memory stick. put the battery back in to test the Pandora. It should power the PSP on but give a black screen.
that's good.
now put the stick back in and put the battery in afterwards and a menu should show up!
choose "Install M33" and let it do it's magic.
once it's finished, pick restart. your PSP should go to a fresh 5.00 M33-4 Menu XMB, go to your system settings to make sure it worked.
If not, take the battery out, and put the charger in and start it. it should run.
then go run Hallcat's pandora installer and go to battery options, and run "Set serial from backup". your battery is now back to normal.
DL your 5.00 M33-6 update
here, and run it.
Congrats, you're now on 5.00 M33-6. Fuck GEN-B and it's buggy bullshit.