kobs-ng could write two copies for firmware(bootloader). it is default.
since uuu 1.3.82 supports build-in script for nand "-b nand " with need nandbcb in u-boot, which does the similar as the kobs-ng.
And I suggest you to use emmc, because
a. nand flash bad block handling is a problem could not overcome by linux.
b. using nand will spend more time for mass production.
c. the price difference is small between emmc and nand.
example_kernel_nand.uuu in binary demo release.
.........
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# write boot loader
FBK: ucmd source /tmp/mtd.sh; flash_erase /dev/mtd${nandboot} 0 0
FBK: ucp _flash.bin t:/tmp/boot
FBK: ucmd source /tmp/mtd.sh; cd /tmp; if [[ ! `cat /sys/devices/soc0/soc_id` =~ .*MX8(Q|DXL|MN|MP).* ]]; then pad="-x"; fi; kobs-ng init $pad -v --chip_0_device_path=/dev/mtd${nandboot} /tmp/boot
# burn FIT
FBK: ucmd if [[ `cat /tmp/mtd.sh` = *"nandfit"* ]]; then source /tmp/mtd.sh; flash_erase /dev/mtd${nandfit} 0 0; dd if=/tmp/boot of=/tmp/fit; nandwrite -p /dev/mtd${nandfit} -p /tmp/fit; fi
internal uuu -b nand
uuu -bshow nand
uuu_version 1.2.39
# @_flash.bin | bootloader
# @_image [_flash.bin] | image burn to nand, default is the same as bootloader
# This command will be run when i.MX6/7 i.MX8MM, i.MX8MQ
SDP: boot -f _flash.bin
# This command will be run when ROM support stream mode
# i.MX8QXP, i.MX8QM
SDPS: boot -f _flash.bin
# These commands will be run when use SPL and will be skipped if no spl
# SDPU will be deprecated. please use SDPV instead of SDPU
# {
SDPU: delay 1000
SDPU: write -f _flash.bin -offset 0x57c00
SDPU: jump
# }
# These commands will be run when use SPL and will be skipped if no spl
# if (SPL support SDPV)
# {
SDPV: delay 1000
SDPV: write -f _flash.bin -skipspl
SDPV: jump
# }
FB: ucmd setenv fastboot_buffer ${loadaddr}
FB: download -f _image
FB: ucmd if test ! -n "$fastboot_bytes"; then setenv fastboot_bytes $filesize; else true; fi
# Burn image to nandfit partition if needed
FB: ucmd if env exists nandfit_part; then nand erase.part nandfit; nand write ${fastboot_buffer} nandfit ${fastboot_bytes}; else true; fi;
FB: ucmd nandbcb init ${fastboot_buffer} nandboot ${fastboot_bytes}
FB: Done
