iMX8 BootROM and illegal eMMC content

[peterhaake]

Hello,

I would like to know what happens if one overwrites he content of the eMMC on the EvalKit x-MCIMX8M-EVK and the BOOT pins are set to internal boot with eMMC as its source ?

I cannot connect with the SEGGER  Debugger anymore. It seems everything JTAG has been disabled.

If I change the BOOT pins to Serial downloader everything works fine again...

br, Peter

[jamesbone]

Hi,

If you overwrites the content of the eMMC, the boot ROM code fails to boot and change to the next option, if this has been hardwired but the ROM code never finds something to boot, then moves into the Serial Download Mode.

Have a great day,
TIC

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[peterhaake]

Thx for your answer.

Unfortunately that doesnt explain why the communication over JTAG (BScan and Emulation) isnt working after overwriting the eMMC.

Besides, if I choose Serial Downloader mode over DIP-Switches on the EvalKit it still works.

So where is the Difference between Serial Downloader, (I wil call it here) from BootROM, and Serial Downloader choosen by Hardware ?

br, Peter