iMac Pro 2017 A1862 SSD Upgrade & Recovery mode

[tommy97]

Hi,

we've got iMac Pro 2017 which having a problem with SSD, iMac come with 2 SSD's 1TB, it was having a problem with the SSD so we get the replacement, installed in and iMac is stuck in recovery mode, tried to restore it & revive, nothing worked - error 4010. After installing old drives now we're having the same problem that the device is in recovery mode. Previously after swap of the SSD iMac worked on the old SSD however after attempt of revive on the new SSD machine stuck in recovery mode, I can go to DFU but the same result with error 4010.

Any ideas what might've happened and how to resolve that problem?

[mon2]

https://discussions.apple.com/thread...93?sortBy=best

[tommy97]

Hi, now I'm stuck on the error 9, tried on 1-2-3 ram's, did not change anything, checked on customer old SSD, on the new is exactly the same. (SSD's are installed in the right order)

[mon2]

PS: How is this thread in the laptop forum?

Hi. Ditto on the same model in for repair. Were you able to make any progress?

For our case, the power sequence stops @ PP1V8_S5. This unit will end up in the landfill if we cannot fix it. May try to do a bypass for this PP1V8_S5 rail.

The PP1V8_S5 appears to be supplied by BUCK3_SW (PMIC @ U7800). Has anyone attempted to replace this part with success?

Where is the enable for this rail? Is it internal? Can any similar PMIC be used for the replacement?

BTW - the switching leg of this regulator IS WORKING @ PP1V8_SLPS2R (BUCK3_LX0).

PP1V8_S5 is not shorted but has 0 volts. This rail powers the flash IC and many other parts onboard.

Can enter DFU using a remote macbook with proven USB cables running Sonoma but repeated attempts result in Error 9. According to a find on the internet by 'Barry', the DFU issue with Error 9 is a software fault.

Unable to REVIVE / RESTORE this logic board. Did see a small fan spin during the DFU process.

Welcome all feedback.

[mon2]

Suspecting this to be an issue of the host and target OS not matching.

Tested with many known good USB cables - no difference.

Inspected the entire board - could not locate a fault. Have not (yet) inspected with a thermal camera but no shorted parts from the hours of debugging.

Can enter DFU mode with ease using the shorting PCB pads.

Will roll back the host machine OS and attempt again. We know so far that the target is NOT on Sonoma. About 6 months ago, we did have a client with a dead macbook who was on Sonoma so 'assumed' that the latest and greatest OS is desirable for this DFU process but forgot that this is an Apple design - not much is logical.

Will update this thread after testing.

[mon2]

No luck in attempting with an older Configurator on Ventura OS. Same USB timeout error. This makes sense since the CPU / PCH rail is not yet on. The PCH is the host USB controller.

Also have no VBUS on any of the USB ports yet 5v is enabled on the board. The local USB load switch is enabled by the PCH which is not yet powered.

If either of the fans is not properly seated inside the molex SMD connector, the local fan will spin at hyperspeed.

[mon2]

Came across this power sequence charge for the CALPE PMIC which should help:

https://logi.wiki/images/8/86/820-01...r_Sequence.pdf

Will continue to review. Issue may be corrupt T2 firmware which is required for a proper DFU. The T2 controller communicates with the PMIC to enable the missing power rails (PP1V8_S5). This is a catch-22.