Lost all four.
I'm not sure if this is relevant, but didn't a BA 742 have all four donks choked by pumice dust from a volcano in Jakarta? In the eighties? I accept that actual total loss of thrust was not the whole period of the incident and may thus disqualify it from the terms of this discussion. I believe the engines where shut down or flamed out of their own accord, one at a time until there were none. Then, after huge effort on the part of the crew and the fact that the aeroplane had flown out of the plume, engines were restarted one by one.
From memory, the incident happened at FL370 and they got one engine - the one they shut down at the beginning of the incident - restarted at around 12,000 which slowed the descent to about 300ft/min.
Digressing only slightly to the engines themselves, this incident demonstrated, to me at least, just how bomb proof modern High Bypass Fan jets are. I recall seeing photographs of one of those engines after partial tear down and the damage from accreated pumice was massive.
Anyway, I offer all four engines out - BA??? 747 198x?
Roger.