I’ve got a real pain of a problem here and I’m looking for some outside opinions on the best way to resolve it, here goes:

Recently purchased an R36S Retro Handheld (https://r36sgameconsole.com/) and installed Rocknix (https://rocknix.org/) on it. When loading arcade games in RetroArch (1.20.0) the core it’s using is MAME(0.273 (unknown)). My MAME collection is 0.256 (downloaded from Internet Archive once upon a time). Everything is already scraped, I would like to avoid downloading an entire new collection to work with the 0.273 core. What’s the best course of action here?

1. Copy a compatible ARM 0.256 core to the device (where do I find this/how do I compile it myself?)
2. Is it possible to convert my rom set to 0.273 and then I’ll just switch the locked cores on all my other devices from 0.256 to 0.273?
3. Just download a new collection

Something else I’m not considering? I know there’s historical reasons for why MAME is managed like this, but in 2025 this seems untenable.

Thanks for any help or advice you can offer!