Hello, I am planning to buy a GBA Everdrive soon. My question is, can GBC games use the RTC?
Yes it can, first do the Pokémon E/R/S Boktai RTC trick (Set the time to 12:02 am in Pokémon and save, then open Boktai 1, set at your current date, save your data just to be sure), then select the gbc rom, for example Pokémon Gold, go to ROM Settings, change the RTC option to ON, Apply the change and there it is!
Just remember, after using the game's save option, press L+R so the data will be truly saved