Here is a multi boot loader for picocalc
combined with PicoMite and SD boot into one single uf2
In first boot up ,Default app is PicoMite , if no sd card or no firmware bin files, user can still launch PicoMite as Default app
If other bin has ran , user can launch it as the last ran app from menu [Last app] to avoid repeated flash read and write.
put all bin files into firmware folder on SD Card
bin files are re-compiled with offset 152k flash address
here is a pre-compiled quick try version for pico1 in PicoCalc
welcome to test