I have been using MicroPython on my Pico for a couple months and recently decided to give CircuitPython a try. CircuitPython loaded onto the Pico fine and I did my testing without any issues. However, when I then tried to put MicroPython back on the device, I ran into some problems.
After copying the MicroPython UF2 file the Pico reboots but is no longer recognized as a USB drive on either my Windows PC or my Raspberry Pi. When I start Thonny the shell window displays two error messages "Warning: Could not sync device's clock: can't import name RTC" and "Warning: Could not validate time: can't import name RTC". The Thonny shell then shows the REPL prompt and appears to work fine. I can even paste code into a new Thonny window and save it to the device. The code still seems to run fine and will turn the LED on and off for instance.
I have also tried connecting over the /dev/ttyACM0 serial port using dhylands/RSHELL and that no longer works, it simply hangs on the "Trying to connect to REPL" line until ctrl-C is pressed.
I have tried using the flash_nuke UF2 file which did erase all my data but didn't change anything regarding the MicroPython reinstallation.
If I reload the CircuitPython UF2, the Pico once again behaves normally, showing up as a USB drive when attached to either my Windows PC or the Raspberry PI and Thonny's shell connects without any errors.
I did see an earlier post which indicated there shouldn't be any issues going back and forth between MicroPython and CircuitPython so I'm hoping this is an issue with a recent CircuitPython build and can be resolved.
Thanks!