Usually Linux applications display help when the switch '--help' is used.
rpi-update start normal operations
root@raspberrypi:/home/pi# rpi-update --help
*** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
*** Performing self-update
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 12762 100 12762 0 0 40454 0 --:--:-- --:--:-- --:--:-- 40514
*** Relaunching after update
*** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
*** We're running for the first time
*** Backing up files (this will take a few minutes)
*** Backing up firmware
*** Backing up modules 4.4.50-v7+
Invalid git hash specified
Usually Linux applications display help when the switch '--help' is used.
rpi-update start normal operations
Please consider implement help. Thank you.