Pybytes - can't delete device file

[numbat]

In Pybytes, under Device Files, I'm unable to delete a badly named file. 'maincopy.py' will not go away. Originally there was a space in the file name: 'main copy.py'. Now it can't be gotten rid of. Also, any entry in the Pybytes terminal causes board to reboot - I think this is also related to the bad file.

[jirkakrepl]

On a device, you can call os.mkfs('/flash') this will delete all the files in the /flash directory