I have attached a patch adding a program that allows re-reading the partition table. This is often used on embedded systems booting from SD/USB devices that need to resize partitions on first boot.
Isaac Dunham suggested xprintf() should call fflush() instead of ferror(), and posix-2008 doesn't say if fflush() covers ferror() (or can return success when the stream's error state is set), so call both.
Brush the dust off toysh.

Simplify the config micromanagement tangle to just a single "interactive"
option. Fix an unused variable and wrong variable type.