Chosen Solution
After my mac white screen’d I tried all sorts of recovery, no luck, it just boots to white screen before any recovery tools (disk util etc) show. Diagnostics gave me the error code: 4mot/4/40000003:hdd 1226 - which I researched was most likely the HDD fan. I took it to the Apple store and they said they think the HDD needs replacing but since it’s a legacy product I’d have to do it myself, I questioned whether the HDD had broken since I’d managed to access it fine in Single User Mode, but I figured they know more than me.. I installed a new SSD upgrade in last night… I’m still getting a white screen, I’ve tried to run online recovery mode to format and install the OS but after it downloads successfully it just white screens halfway through the apple loading screen, so I can never get to disk utility or installing the OS. I’m starting to wonder whether it’s my graphics card, but nothing came up in the diagnostics test for my GPU… What else could it be? It doesn’t seem like a broken fan would stop it booting.
At this point you should be able to boot up in Safe Mode as well. Restart again this time pressing the Shift (⇧) key. Doing the Target Disk Mode first resets the SMC latch which is set when the Discreet GPU fails. Sorry to say this is not uncommon in this series when the Discreet GPU fails. You might be able to get a few more miles out of it by baking the board in an oven or just replace it. Do keep in mind its a big job as you’ll need to take the logic board fully out.
