@rocketman I also had problems with the PSP emulator on RPi3, and I've seen other reports about that, the "solution" I found was:
Go to the folder \share\system, in the file recalbox.conf, find the line "dreamcast.videomode =" and add just below it the line: "psp.videomode = default" (without quotation marks, obvious)
In addition, in the folder "\share\system.emulationstation", in the es_settings.cfg file, find the line "<int name =" MaxVRAM "value =" 200 "/>", and change the value from 200 to 80, getting : <int name = "MaxVRAM" value = "80" />
With this, the PSP emulator is able to work most of the time, and if the game does not enter immediately, just go back to the EmulationStation main screen, or wait a bit, to try again, that the game will start, without having to restart the Recalbox.
Some users reported problems due to themes with 1080p images, but others claim that even the default theme does not allow them to run PSP, so I do not know how much that actually influences (even more so because the info on this is more than 2 months ago.)
I know that @substring does not like my solution, but it worked for me...
