Should be working straight away, there is an extra check on the box type (AUTOKIT or not) so be sure to use the good file:
- U2W_Update_2021.03.06.1343.img renamed to U2W_Update.img if Blue UI
- U2W_AUTOKIT_Update_2021.03.06.1355.img renamed to U2W_AUTOKIT_Update.img if Red UI