The following if correct may explain why the EBHA to SPLR # 6 didn't operate. Could it be powered by AC Bus 2 which didn't receive an automatic power supply transfer therefore HYDs but no electrical power!
May also explain the loss of LEGRS power to ALTN brakes.
More Scuttlebutt from the Antipodes ( unverifiable source)
1. Bus #2 is supposedly automatically powered by Bus #1 in the event of Engine #2 failure - didn't happen.
2. Buses #3 & #4 will supposedly power Bus #2 in the even that the auto transfer from Bus #1 fails - didn't happen