When BIOS updates fail in this way, there is a single cause: the BIOS is having problems with memory operation.
The BIOS is initializing the memory controllers (typically) according to the SPD data provided. The memory is not operating properly at these settings. This results in a bus lockup. The BIOS enters recovery, as a result of watchdog timer wake, and reconfigures the memory to operate at default settings instead. It is able to continue then but, as a result of it's reinvocation via the recovery process, it's knowledge of the BIOS update in progress has been lost. In essence, it has forgotten it was doing a BIOS update.
So, what do you do about it? It's simple: reconfigure the BIOS to only operate the memory using default (1333) settings - or use different memory.