I enhanced the custom firmware to automatically dump the built-in rom files to a /rom folder on your SD card the first time it runs if the control file is present. So you start with the core set of roms, box art and config file all running from the SD card and then can customize it with your own additions and subtractions. Many thank you's to Flojomojo! Since you have not answered the question "are you the firmware fairy?", I'm going to take a guess and say it might have been someone else who didn't want to be named and gave you the file to upload. Feel free to correct me if I'm wrong.

Atari 50th Anniversary Flashback Gold from Review of the Atari 50th Anniversary Flashback Gold from

This console is totally plug and play, so you don’t have to worry about installation or charging. Just plug in the included AC power adaptor, connect it to your TV with the included HDMI cable, grab 4 AAA batteries for the controllers (2 batteries each), and you’re good to game! Additionally, I changed the box art for the FB9 versions of Frogger and Space Invaders. The FB9 uses the original 2600 box art, but I wanted to use them for the newly loaded 2600 roms. The attached "frogger-spaceinaders.zip" swaps out the FB9 art for new box art utilizing their original Arcade flyers, but have been named the way they were in the original ini file. The 2600 versions (in the "arcade_collection.zip") are titled "Frogger2600" and "SpaceInvaders2600". I have been obsessed with this CFW for a few days now. Attached are a bunch of box art and game instruction files I made that can be included in the "all-games.ini". These are official and homebrew Arcade ports and some Activision titles. Putting a /GAME folder on your SD card and dropping .a26 rom files there to load from the "SD Card" menu item still works as before.

Reading your post I can see that you had some nice insights, like the 'rom copy' and the moving the emulator to the SD Card. It's also a good use of the control files logic from the original custom firmware. Lastly, the disclaimer. Use at your own risk. No warranty or guarantees, lol. I have tested both of these firmware with real devices and they work fine for me, but if things go wrong I or somebody else may or may not be able to help you. For now I was thinking to share a Google Drive folder with ini files and already resized box art. I'll probably include this file, but may individual .txt files for additional games that people might commonly want to add. I'll put something together in a day or two. Still thinking to build a tool for this file.

Flashback 9 Gold CFW to load roms and boxart from SD Flashback 9 Gold CFW to load roms and boxart from SD

The latest official firmware included the entire /rom partition contents. it's possible to dump the NAND flash from the device, but it wasn't necessary as I was able to extract it from the official firmware.There is a /rom NAND flash partition that contains all of the built-in .a26 roms, box art, a few sound files and the all-games.ini file which configures the menu items. I am also able to remove or suppress any of the built-in ROMs that I might not want. I did a simple test of suppressing the non-original version of Frogger that ships with the console.