X2 — Pokemon Fire Red Exp Multiplier

Go to ROM offset 0x023C1E (2 bytes before the return). Change:

Through routine analysis, the function that calculates EXP after a battle is located at RAM offset 0x08023B94 (ROM offset 0x023B94 ). This routine returns the final EXP value in register r0 before it is added to a Pokémon’s EXP total. pokemon fire red exp multiplier x2

0x08023C20: 4770 bx lr (returns)