For people who have problems with the update, try this:
Before put the lens into camera:
- Baterry info -> INFO -> DELETE ALL registered batteries
***** Try with the battery at 100%, fresh from the charger !!! If don´t work try with another freshly charged 100% ******
5D Mark III v1.1.3 without grip
Canon EF 40mm 2.8 STM ** DEAD **
CF with lens firmware
With my first battery, don´t work (crash, red light, ...)
With my second battery, the same (2698%Done, crash)
With my third battery, WORK !!! DONE !!
I think the problem is firmware check the battery, I don´t know....
Regards from Spain