@abunille said in Can I use the micro SD I have made for my Pi 2 on my new Pi 3?:
In the downloaded zip file of recalbox there are installation files for pi1,2,3.
When starting your pi, the system recognizes which hardware is present and takes the appropriate installation package. And your installation was on pi2.
The pi versions differ SoC (Broadcom), CPU, architecture, ...
Indeed each recalbox version is builded with specifics settings from each RPI (as said by @abunille different cpu using different instructions, etc....) and some emulators are specifics to a RPI version (other rpi not powerfull enough to emulate a system, like dreamcast, psp that are rpi3 only etc...)