Wiz,
We operate quite a few 777's too
I was quoting from the FCOM QRH:
"The recommended flap setting for landing is F20. F30 may be used if the landing distance available is critical & go around performance permits it"
F30 is permitted in the single engine case with the "performance permitting" caveat.
The overweight landing checklist however asks you to choose from:
-Landing gross weight is greater than landing climb limit weight or
one engine is inoperative
-Landing gross weight is less than the landing climb limit weight and
both engines are running normally
Therefore the Boeing QRH directs you to use F20 if you are over max landing weight with engine inop.
Regards