connectcore 6UL som board uboot recovery

I have custom board based on connectcore6ul som board which has Nand flash, JTAG and UART console only(No USB, No Ethernet, No serial downloader boot mode ). There was on factory uboot boolader on my board and usally i do flash images by loading uboot, kernel, RFS to ram and ram to Nand flash via uboot nand commands. But accidentally i flashed other board Uboot bootloader on my board Nand flash. Now board is hangs on uboot dram initialization. Not able to access uart console and through jtag-openocd not able initialize the DRAM. pls help me on this how to recover.

Digi uses ARMDS-5 JTAG debugger with cc6ul:

You can also try to implement Serial downloader via castellated pads of the module