820-3437 that works fine, passes ASD, and will read from USB drives, but for some reason will not boot from USB drives? I've seen this before in the past with bad ME regions, but that doesn't appear to be the case on this one. I checked closely, and there's no evidence that anyone ever messed with the chip area, and the system serial and board serial are both correct in the EFI dump, so I don't think it's been tampered with. I forced an EFI update anyway to be sure, and it still hangs when booting from any USB external drive (have tried 3 that all work perfectly/boot normally on an identical machine). Internet recovery seems to work fine, and will complete a remote restore of OSX. Board boots to SSD normally, works fine, no issues. USB ports do work, and I transferred several files using each USB port to make sure there was no latency issue, and all seems fine. The only issue is the board will not actually boot from an external drive. No liquid damage to the board.
Sort of a weird one, and I'm not sure how to proceed. Anyone ever seen anything like this?
Sort of a weird one, and I'm not sure how to proceed. Anyone ever seen anything like this?