EMD-041 Flash Controller ScCmd Response Error

asdrubale · Friday at 9:45 PM

Hello everyone,

Lately, I seem to be getting nothing but nightmare boards. I received an EDM-041 board that had already been worked on by another technician. It arrived without the BIOS chip (which I rebuilt), without the retimer (which I reinstalled), and without the W2251 60NGDTO, which I sourced from a donor board.

However, I have not been able to get it to boot. The power-up sequence progresses to approximately 130 mA, and I get the following UART error:

80871060 FFFFFFFF FFFF0042 10000000 2039 0000 FFFF FFFF:25 (Flash Controller: Flash Controller ScCmd Response Error)

I tried replacing the CXD90070G, but I get exactly the same error. Just to rule it out, I also replaced the DDR4 memory module, but that made no difference—the error remains unchanged.

All voltages and voltage drops around the RT5127 are within spec. I cannot find any shorts on any of the main lines routed through the CXD90070G. The voltage-drop measurements on the data lines going to the APU also appear normal.

I’m reaching out to anyone who has experience with this specific error code. Is there anything else I should check that I may have overlooked?

Thanks in advance.

thesjaakspoiler · 2026-06-20T08:23:18+0100

Never had those error codes so I can't say for sure.

If your voltages and chips are fine, then maybe the CXD90070G just can't communicate with the flash chip.

Looking at the schematic of the EDM-010/020, I notice there are a lot of resistors around the BIOS chip and with SPI communication those resistors need to be present and the right values.
If you got the board without a BIOS flash chip, I would not be surprised that the previous technician just blew it off the board along with other components.

Inline resistors on pin 2 and 5 should measure 47 ohm and the pull up resistors on pin 1,3,7 should be 4.7k.
I don't have manuals for the EDM-041 but I presume it uses the same flash chip.

Good luck, I admire your attempts to fix such boards.

asdrubale · 2026-06-21T21:22:57+0100

@thesjaakspoiler Thank you for your reply. In fact, the resistors present around the BIOS chip on the EDM010 and EDM020 revisions had already been removed starting with the EDM033 revision. In the Slim versions, they are no longer used. I carefully inspected the entire board under a microscope and found no missing components. Unfortunately, I will have to give up, even though the issue remains somewhat frustrating. My experience and expertise reach their limit at this point, and I do not know where else to investigate. Thank you.

EMD-041 Flash Controller ScCmd Response Error

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