iMac efi

i found this on the back side of the logic board.... a large pad arrangement that looks like it had a connector of some sort on it.. there is solder on the pads and the flux is not cleaned up.

so here's what i've determined so far...



ground will just attach at a board mount point.
i've gotta do some other stuff, but then i'm going to test the resistance on these points and make sure they're viable.

All test at about .5ohm except clk which is 42.9

i've polled these values at the debug header pads. can't seem to find CS there tho.

i've successfully made all of the connections



the green LED on the MLB lights up, so i've definitely got 3.3v and gnd.

i can't get a read on the chip, no EEPROM found.

has anybody gotten far with this sonofabitch?

That's pretty much as far as I've gotten with it also, EEPROM not found doesn't matter what I try.

Yeah. I put the MLB back in the chassis and was working on it, but my son knocked the pi over and all the wires shorted and now it's fucked

Shit

I was going to attempt a read with the chip powered internally, but now I've got to fix whatever's been broke.

reverendalc wrote:

i've polled these values at the debug header pads. can't seem to find CS there tho.

i've successfully made all of the connections

the green LED on the MLB lights up, so i've definitely got 3.3v and gnd.

i can't get a read on the chip, no EEPROM found.

has anybody gotten far with this sonofabitch?

Not sure if this applies here... read this dangerousprototypes.com/forum/viewtopic.php?f=40&t=6668

That's great lol. Too bad I've tried all that. It seems that apples architecture prevents externally powering the chip in circuit. Judging by the green led turning on, way too many components are powering on and either there's a voltage loss (I should've metered it before all hell broke loose) or something is turning on and locking the chip.

I don't want to remove the chip, I want to create the easiest reproducible process for the next guy who drives down this road on these tires.