bash's `read -t 0` only TESTS whether input is available; it does not
consume the bytes. So the drain loop `while read -t 0 ...; do :; done`
spun forever the moment any bytes were pending (e.g., the DSR reply
sitting in the tty input buffer after gum style sent CSI 6n).
That hung the configurator at the first step() title screen — blank
prompt, blinking cursor, no keyboard form.
Use `read -t 0.05 -N 9999` once, which consumes up to 9999 bytes with
a 50ms timeout. Always returns after 50ms whether there's data or not.
Single call replaces the while loop.
Ryan Hughes
8734136908