Just had an epiphany moment where it finally clicked that
retroarchcustom.cfg is regenerated each load (duh https://wiki.batocera.org/advanced_retroarch_settings) ….
That clears up some of the confusion as to why my mappings have been going sideways. Now I have a different/related question
I have two always plugged in controllers, and they always register as dev-0 and dev-1 (good)
Ive set a couple emulators to default to dev-2 and dev-3 (ie NES console) via
which works .. however, this batocera/retroarch regen seems to still use the key bindings of dev-0 and dev-1, which is not correct for the other controllers. ie start/select on dev-0/1 are 8/9 and its 6/7 on the the other devices. Im thinking Im missing something to trigger batocera to use the correct bindings when it reges