No. It is possible to downgrade some PSP 3k, but it is not possible to downgrade below the firmware it came with. The first version PSP 3k came with 5.03, downgrading it below that will brick it permanently.
Also I wouldn't downgrade a PSP 3k at all, chances for a brick are too high. You might want to look into 6.20 TN-A or TN-B, there is an iso loader for it and it doesn't require downgrading. But it is not permanently, there is no permanent custom firmware for PSP 3k.
Xbox 360: Slim untouched with a faked 320 GB harddrive for XBL, phat with LT 3.0, played Halo early, so going on live would be an instand ban, also with a faked 320 GB harddrive
PS3: Untouched 160 GB Slim, 60 GB Fat with latest Rogero and 160 GB internal harddrive.
PSVita: hardly ever play it
GameCube: Black with a Viper chip installed. With gameboy player. Trying to get a Wavebird controller.
What in "There is no permanent custom firmware for PSP 3k" didn't you understand? Check out 6.20 TN-A or 6.20 TN-B, there is an iso loader for that too, so you can play your backups.
Xbox 360: Slim untouched with a faked 320 GB harddrive for XBL, phat with LT 3.0, played Halo early, so going on live would be an instand ban, also with a faked 320 GB harddrive
PS3: Untouched 160 GB Slim, 60 GB Fat with latest Rogero and 160 GB internal harddrive.
PSVita: hardly ever play it
GameCube: Black with a Viper chip installed. With gameboy player. Trying to get a Wavebird controller.
Originally posted by highvolta: yes you can downgrade but NOT to 5.00 M33-6, you can downgrade to 5.03 and then install gen cfw. downgrading can be done via 6.20 TN-B
Which I totally wouldn't recommend when using a PSP 3000 as it is not neccessary and too dangerous. 5.03 GEN is also not permanent, so there is no reason why you won't use 6.20 TN. Also you can't downgrade all PSP 3000 to 5.03, there are atleast 3 different versions of motherboards for PSP 3000 and only the earliest one can be downgraded to 5.03. If you're on the wrong one and try a downgrade: Congratulations, now you got a spare UMD drive, a spare housing, a spare screen and a spare useless non-functional mainboard. If you are on the right one and the downgrade fails, see my last sentence.
Xbox 360: Slim untouched with a faked 320 GB harddrive for XBL, phat with LT 3.0, played Halo early, so going on live would be an instand ban, also with a faked 320 GB harddrive
PS3: Untouched 160 GB Slim, 60 GB Fat with latest Rogero and 160 GB internal harddrive.
PSVita: hardly ever play it
GameCube: Black with a Viper chip installed. With gameboy player. Trying to get a Wavebird controller.
There is a signed 6.35 PRO HEN program that will run from xmb. No longer need to perform chickHEN on psp-3000.
While this isn't yet a permanent hack (if you restart your psp 3k you'll have to "re-hack") it's a whole lot faster than trying to load a bad photo file over and over again until it finally crashes.
I'm still waiting for a full CFW or signed ISO loader for psp 3k. It can't be more that a couple of weeks away. Those keys they found inside the ps3 have opened the sony world wide open!
