Imac late 2009 27 inch refuses to boot High sierra

[Sebasboy]

hello good day.

i got a 27 inch late 2009 core 2 duo imac here that works perfectly with el capitan.

but if you either upgrade. or clean install high sierra. it wil get stuck on this screen after installation .

if i boot it into safe mode by holding shift it boots fine (minus the lag and no gpu acceleration)

but in normal mode it just freezes at this.. loading bar with a circle.. i cant find anything on google..

the genius bar cant do anything due to corona and it being obsolete.

it's being installed to a new 120 gb ssd.

like i said. clean install of elcapitan works as it should but high sierra (which is native supported for both the imac and the gpu since its a 2010 gpu) it stil freezes.

i checked the verbose log and it wil load some text and then stuck on a black screen with 1 single cursor and every few seconds blink 2 likes of text relating to "oslockscreen"

anyone have any tips?


the imac is using a mid 2010 imac gpu and a mid 2011 wifi card (though turns out besides 2 vs 3 antennas its the same card)

 

[richardsan]

i have this model. the only physical upgrade is the HDD.all software installed by me. have you zapped your Pram, or checked your clock' battery? i'm about due to change mine, as those settings (like start up chime) don't always announce.
just getting ready to see if i can get catalina installed on this old cranky beast. and having a 'full capacity not recognised' with a new 4TB HDD. it's limiting to <2TB...