Replaces the instruction which would otherwise take a life away when the player is put back at the start. The new instruction clears the sign flag, so the jump to the game over screen is never made.

C2FA	LD HL,A721
C2FD	DEC (HL)
C2FE	JP M,ShowGameOverScreen

To:

C2FA	LD HL,A721
C2FD	XOR A
C2FE	JP M,ShowGameOverScreen