This video is on creating a reproduction cart for the Atari 7800 to allow play of home-brew games on the real hardware. You can use this method for many of the roms out there as long as they fit on a single eprom.
Basically you flip the hex inverter onto its back, sorry if I got the pin numbers wrong when I said them, it was late. I wired it correctly in the video, just said the wrong pin numbers when referring to the hex inverter.
A 27256 or 27c256 32K EPROM a 7404 or 74LS04 Hex Inverter a standared 32K Atari 7800 cart such as pole position
Correct wiring of the hex inverter on the back of the board.
pin 14 on 7404 goes to pin 28 on the eprom (this is vcc) pin 8 on the 7404 (4Y) goes to pin 22 on the eprom (OE) pin 7 on the 7404 is to the ground pin 9 on the 7404 goes to the trace we cleaned off (the wire in the video).