i.mx6 - how to read NAND with JTAG

[skyflyerskyflye]

Hi all.
I have a device with this hardware onboard:

CPU - IMX6S6 (cortex-a9 800 Mhz)
Memory - NT5CB128M16FP (ddr3)
SLC NAND S34ML02G1 (spansion)

The device was a bricked as a result of the incorrect firmware flashing.
Now it is in a boot-loop state.

Serial console is disabled some way, U-boot is loading and works fine, but we don't have an access to it. No serial output. JTAG interface is a present on motherboard, I can connect to cpu with J-link.

My target is to be able read and write Nand flash memory via the interface J-tag. Since the serial console is disabled on the device (somewhere inside u-boot), Jtag is only available way to unbrick the device.

I know that for read/write Nand through J-tag we need make a some program, download it to RAM and execute.
U-boot (as far a know) also can work with Nand Flash memory. May be it is a way for complete the task.

But how to do this - I need to compile the u -boot, load into memory, run it, then enter the console?
On the board, I found the pads, that lead to cpu's UART0-UART4 ports. I think, its can be enabled in U-Boot config.

1) Which U-Boot should I choose for this task?
2) How to correctly configure and compile it?

Or suggest a different way, perhaps more simple.

[igorpadykov]

Hi skyflyer

please check sect.1.4.1 Using JTAG Tool for Debugging attached Porting Guide and
https://community.nxp.com/thread/315248
http://lists.denx.de/pipermail/u-boot/2016-June/258230.html

Best regards
igor
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