Commodore 64: Cyberload F2 loader
Threshold : Varies between tapes.
Endianess : MSbF
The loader code (LOADER2) is contained (partly enciphered) in the FORMAT1 files, it is only responsible for loading *one* file containing LOADER3.
Pilot byte : Varies between tapes (commonly $0F) (*128)
Sync byte : Varies between tapes (commonly $F0)
Header (XOR enciphered)...
2 bytes : Load address (LSBF)
2 bytes : Data size (LSBF)
n bytes : Data (XOR enciphered).
1 byte : always $00
Notes:
Because LOADER3 typically loads on a page boundary, you can usually (NOT always) read the correct xor DECIPHER value in the very first byte, ie.. load address low byte will decipher as $00, so just read its ciphered value and use it decipher all header bytes. (it's often $AE but NOT always!)
To decipher with certainty, you will have to "snoop" the loader code.
The LOADER3 program is stored in this format, when correctly deciphered you will find the string "HACKERS, FUCK OFF AND DIE" inside its file.
The (n bytes) data is also XOR enciphered but uses a different key. it is usually $D2 but to be sure you will have to "snoop" the LOADER2 program code.
If the game is multi-load then you will find a file of this type later in the tape also. (before the additional 'multi-load' files.)
