"Fast" is relative here. According to the youtube link OP posted in CNX comments, it takes 6 minutes to boot to shell. Still, better than two hours @dmitrygr's ARMv5-on-AVR emulator took.
yeah, 240MHz 32-bit cpu does help compared to the 20-mhz 8-bitter :)
Although, Xtensa can execute out of RAM, so here a JIT could be used for a larger speedup. Maybe i'll build a RiscV-to-xtensa jit some day when i'm bored
