Each one of these commands (r, e, i, s, u) takes or can take a few seconds to complete successfully, so let them do their thing.
In particular, if you have HD-activity LEDs, watch and wait until they stop blinking - after the 's' (sync) key.
Each one of these commands (r, e, i, s, u) takes or can take a few seconds to complete successfully, so let them do their thing.