  First Homebrew Code on 2.00
 -----------------------------

1. Set wallpaper to frame_buffer.png (without overflow.tif present
   in the PHOTO directory, or it will crash).
2. Add overflow.tif to the PHOTO directory, and open into the photo
   viewer. Custom code to paint the screen! Or to write a homebrew
   app! Not to run illegal games.

  How It Works?
 ---------------

1. The PNG contains a small amount of code in a known, fixed place
   (the VRAM). If to look closely at the wallpaper, sees small
   coloured pixels in the right down. The pixels are Allegrex
   opcodes, with the highest byte all zero for the ALPHA. These
   pixels do:

     syscall 0x20C7         ; sceKernelDcacheWritebackInvalidateAll
     slt a0, zero, sp       ; put 1 into a0
     sll a0, a0, 6          ; put 64 into a0
     addiu a0, sp, a0       ; get screen painter address over SP
     jr a0                  ; jump to the screen painter
     nop                    ; branch delay slot

2. The TIFF contains also some code and a buffer to trigger the
   known BitsPerSample overflow in libtiff in the photo viewer.
   The buffer makes a jump to the VRAM which has the PNG colours
   by overwriting the safed ra (return address) on the stack.
   The VRAM code uses SP and calculates the address of the buffer
   then runs it. Then it jumps there. The screen is yellow as
   the colour was 0x12345678 in Hex.

PSP Users:

We didn't do this so you could steal from Sony and game companies.
We believe in OSS. There are plenty of amazing programs that have 
been written for the PSP. Use this as a gift and not as an excuse 
to steal.

Sony:

If you wanted to find us i know you could. This release wasn't 
intended as a way to run pirated software on the PSP. We believe 
that everyone should be able to compile their own code and run it.
Nothing is kept secret forever and i'm sure you know this. 
In the end, if it wasn't us. It would be some one else. 
Fighting it would be like skating up a hill. You did create the
PSP and did an amazing job.

Toc2rta:
To the people of the Toc2rta development network. You're our phone
a friend. With out your friendship this would never of happened. 
I hope this brings you as much happiness as it brings us. 
Join us on irc.toc2rta.com.


Most importantly...  Have fun!