The latest variants of the Analogue Pocket aren't getting along with Everdrive Game Boy flash carts. At least, that's according to the retro handheld gadget's creator, Krikzz, who suggests a new problem running GBA ROMs on the FPGA portable is a hardware issue, but I'm seeing conflicting explanations for why some players can't run backups using the new handheld batch.
At the centre of the Analogue Pocket and Everdrive fiasco is user elfricko. In a post to the Everdrive forum, the player says their shiny new FPGA portable is throwing a "04 File not found" error when using a GBA Mini cart ($125 at Amazon, FYI). After some initial digging, the issue was quickly narrowed down to something replacing the letter "r" with a "v", with the example cited being "romcfg to vomcfg."