Tools needed:

1 ps3 system
2 ps3 hdd same size
1 retail firmware upgrade
1.80 Or 2.15 debug firmware

First format both hdd’s to the ps3 system.

Put debug firmware on a USB stick and start the update. the update will first copy the files to the hdd this is good. Next you system will restart and should take you to screen that reads "push ps button" to begin update (this is past the screen that reads update will start in 30 sec and counts down just push x to continue on) at this point power off the system using the switch in the back. Do not begin the update as it will error out.

Next remove the hdd you just copied the debug firmware to and put in the second hdd. Copy the retail update to a USB stick and start the update when you get to the accept licenses screen don’t push any thing remove the hdd with the system powered on and put in the hdd with the debug firmware on it. Next accept the license agreement and the system will install the update when your finished you will have the debug firmware on your system go to system settings and check version number and you will see the debugging options.

Note for this to work your system must be below or at 1.80 for the 1.80 debug update... and below or on 2.01 for the 2.15 debug update. Just use the next version up from your current firmware version for the retail update.

Now dont get too excited as sofar the debugging options dont actually work and it does take away bluray movie playback

i beleve this same method can be used to downgrade (with the Proxy FW update check bypass)

Custom firmwares arent really that useful on a PS3, kind of a waste of time really (atleast for now). Stick to putting custom firmwares on PSPs its way more worth it.