I guess you are saying “board config” but not BoardID here.
BOARDID is a variable to be put prior to flash.sh. This variable is only used when flash.sh is not able to read the board info. I don’t think this is what you are lacking of now.
sudo FAB=100 BOARDID=3668 ./flash.sh …
As for board config, the one you are using after flash.sh is the board config.
sudo ./flash.sh #BOARD_CONFIG mmcblk0p1
And the board config is actually the pre-defined text files under your Linux_for_Tegra.
For example, you will see jetson-xavier-nx-devkit-emmc.conf.
To use this config board, the flash command is
sudo ./flash.sh jetson-xavier-nx-devkit-emmc mmcblk0p1
Since there is no “P3449-0000+p3668-0001-qspi-emmc.conf” under our default jetpack, you will hit error with no doubt.
You can also write you own board config and it will work if the content is correct… For example, define jetson-ABC.conf and you can use it as jetson-ABC in flash.sh. However, I don’t think this is what you are trying to do now.
For NX production module, use the board config I mentioned above.