After bitbake fsl-image-mfgtool-initramfs and plugging all the bits in to the mfg-tool downloader, u-boot never runs out of nand on my board. I have the usual UBOOT_CONFIG = "nand" in my local.conf and the mfg-tool builds OK. Flick the factory switch, press start, see all the UTP stuff flash past, mounts my board as a drive, flashes uboot, rootfs and kernel then finally sets the boot and other bits. Flick the switch back to run nothing.
If I substitute uboot for one I built based on an imx7s ( warp7 with modified dtb ) it boots fine and runs although a bit clunky. The issue is NOT anything to do with the mfgtool flashing side as I know this very well, it's the actual uboot that's the problem when running the board normally with the factory switch in the correct position.
There's not a single bit of debug that comes out of uboot at run time. What is very suspicious is that using the uboot that comes with the Yocto build I get my board coming up as an HID-compliant vendor-defined device as you would expect if the manufacturing switch was flicked! As mentioned before, keeping all the XML mgftool file the same, swapping out uboot for a imx7's one the board boots fine. I need the the correct uboot for the board however...
Freescale's Community Yocto BSP
Kernel 4.9.88 - Rocko