Hi !

Same iMac G5@2,1GHz here and I confirm the "no bootlogo" (grey screen and Ambient screen but no bootlogo).

For the fan problem, I reset PRam and iMac boots automatically on MorphOS, so no fan at 100% but, some friends have same iMac and iMac shutdown after some minutes/hours because temperature of CPU is too high (fans seem to not start...).
I don't have this problem here for the moment, but the BatteCave (my "MorphOS/Amiga room" ^^) is a bit cold (15°C).

Thank you MorphOS Team for this great unsupport support ! ;)

--
/me will register this iMac asap !

[EDIT]
iMac registered ! (key received 5 minutes after my payement ! Incredible !)
[/EDIT]

[ Edited by BatteMan 29.12.2019 - 08:18 ]