Phat PSP 3.40 oe-a to 3.71 m33...how??

[WingYin]

Hey guys. I have the Phat psp with cfw 3.40 oe-a and want to upgrade to 3.71 m33. but how??...
I know I need Pandora Battery but I dont even know if I have one...
I have to have one if Im running 3.40 oe-a right??
Please help...Im new to this stuff...
I have a mac and want to know what firmware to upgrade to is best.

Please help!!

[Totonzio]

it dawns 3.52-4 m33  >  3.71 m33 > 3.90-3 m33

[FreeK]

downgrade to 1.5 then up to 3.71 m33

i have to say that 3.90 m33 is better though

and dont forget your system update file from sony to do it

[WingYin]

Alright...
so first downgrade to 1.5 and then upgrade to 3.90 m33...
But how do I upgrade it?
I tried to do it with 3.52 m33 and put the files in the exact folders the tutorial told me to. But Im still on 3.40 OE-A.
How to do an upgrade....???