Reading i.MX8MM register values with sdphost

[Sampo]

I am trying to find a way to read register values from a i.MX8MM over USB. The tool sdphost should be able to do it, but I am not able to get it to work and I cannot find sufficient instructions anywhere.

For example, I want to try and read OCOTP_HW_OCOTP_BOOT_CFG0 which should be at memory address 3035_0470:

./sdphost -u 0x1fc9,0x0134 read-register 0x30350470
33 22 33 00
Status (HAB mode) = 305411090 (0x12343412) HAB enabled.

But the bytes (33 22 33 00) are not correct. In fact, no matter what address I give sdphost, it always returns the same four bytes. I know the device is connected and in Serial Download Mode, because I can for example use uuu.

What is the correct command to read register values with sdphost?

Bonus question: is there any way to read registers with uuu? We already use uuu to flash the device and write fuses, it would be handy to use the same tool for reading registers as well. But I looked at sdphost because it did not seem to be possible with uuu.

[JorgeCas · Accepted solution]

Hello,

According to the documentation:

Serial Download Protocol is a set of commands supported by NXP i.MX RT devices in the Boot ROM application’s serial download mode.

I tried on our EVK and also is giving faulty readings. So, I think this tool is not intended to be used on i.MX families as is on i.MX RT families.

Also, in the case of UUU, there is no documented a command to read registers on the board.

Best regards.

[Sampo]

Is there any tool available for reading register values over USB?