I’ve been modding my iPod mini. Largest micro SD memory card I’ve installed is a 256GB. Read it’s fine, so long as you don’t shuffle its files (as music) as It’ll supposedly crash — which I never do anyway.
Has anyone put in a 512GB or larger SSD? These micro SD memory cards are just so cheap nowadays, may give it a try.
Reason for doing this is as for added storage memory, and of course it'll be Rockboxed.