Fresh install on Pi Zero. NES roms not loading on any emulator, GB games run fine.

[potatohandle]

Ahoy there guys,

I've been trying to get a Pi Zero with Retropie working as a present for someone, and I'm having a huge amount of trouble getting NES roms to load on a fresh install. I bought a regular Pi Zero (Non-W) for them, and I have a RPi 1 and a Zero W I've been testing with.

I set up the regular Pi Zero for them, and out of 8 roms, (All from a single source) 4 of them work perfectly. The rest show up correctly, but only shows the loading 'press any button to configure' screen then a black screen for 3-5 seconds, and then boot back to the game selection menu. I've since tried fresh installs on both my Zero W and my RPi 1, and I've struggled to get a single rom working since. Below are the troubleshooting steps I've taken so far. I've reinstalled Retropie from the .img a number of times during these steps. If I didn't reinstall, I at least rebooted between each step.

• Checked md5 checksum of Retropie 4.2 Zero/1 image, no issues.
• Updated all installed packages.
• Deleted all but a single ROM and tried all included NES emulators.
• Tested a large number of GB games with no issues.
• Got ROMs from a different source.
• Loaded ROMs unextracted as .zip instead of .nes (This worked for a single rom out of the 8 that I loaded, but none of the ones which were working on the Pi Zero.)
• Tried loading roms via ethernet (By switching to the Pi1) instead of USB.
• Instructed the emulator to run at 640x480.
• Switched to a 2A phone charger.
• Loaded Retropie image and ROMs using different computer on a different network. Fresh downloads all-round.
• Loaded ROMs into a NES emulator for PC with no issues.
• I'm using a class 10 Amicroe 8gb microSD on my two devices here, and I'm not sure of the brand off the top of my head, but the Pi Zero has a 4gb micro SD which came straight out of a stock Nintendo 3ds.

I'm probably missing something dumb, but I feel like the rom-loading (Into the roms folder) process is to blame. But I don't know how, especially when a fresh install on my Rpi1 had exactly the same issue over ethernet instead of by USB. I haven't tried composite video as I actually don't have an easy means to do so, but I've tried 4 different HDMI screens, one of which has a native res lower than 720p.

Thanks for reading and for any help. I feel bad that I've given a defective present. ._.