System files in a subdirectory about mega65-core HOT 2 OPEN

The startup slot is unknown to the core, so using the slot number will be not easy. The commit hash would be easier to source, as it is even accessible through a register.
Searching will make thinks slower in startup. One main goal was to have a very fast startup, and not do to many things that would make booting less like the "retro" style instant on.
One solution to that would be not searching but always using MEGA65/<HASH> as the directory, so that would be just one change directory at the start (theoretically).

from mega65-core.

I wonder if this feature request is mostly of interest to testers, and therefore could be a secondary mode of operation that's OK to slow down startup (by some amount). Keep / as the first check (presumably the same speed), and only check /mega65/<versionid>/ if system software files required by the core are missing from / before halting with an error message.

from mega65-core.