"Ok, just for reference, if you..." <- > <@diondokter:matrix.org> Ok, just for reference, if you use an RP2040 and want your boot2 to do an integrity check on your flashed data that comes after it and want it to drop back to the USB bootloader if the flash is not correct, then I have bad news for you. It doesn't work. > > The RP2040 has a rom function to do the jump to the usb bootloader for you, but it appears that it only works if the USB and/or some clocks are already initialized. It doesn't do it for you. It's not documented that it does, but it's also not documented that you have to do it yourself. > Doing the init in boot2 won't work because you simply don't have the space for it. I'm a bit surprised. Looking at the bootrom code, I'd say that the "reset to usb boot" ROM function triggers the same initialization steps that also happen on a cold boot. (That of course doesn't mean that it really works - I didn't try it and I may be missing an important detail)