How to program U‑Boot to both eMMC boot partitions (boot0 & boot1) on i.MX95 during factory flashing

[pushpendra2911]

We’re preparing a factory flashing flow for Verdin i.MX95 where U‑Boot must be present in both eMMC boot partitions (/dev/mmcblk0boot0 and /dev/mmcblk0boot1 ) so that a future field upgrade can switch partitions safely. With the default .wic image flashed via uuu , U‑Boot ends up only in boot0 ; boot1 remains empty . We can populate boot1 afterwards from a running target, but we need this to happen as part of the first flash at the factory .

Environment:

• Module/SoC: Toradex Verdin i.MX95
• Bootloader: U‑Boot 2024.04 (nxp_imx)
• Yocto/WIC: image produced via .wks (WIC)
• Flasher: NXP mfgtools/uuu
• Storage: eMMC with /dev/mmcblk0boot0 & /dev/mmcblk0boot1 hardware partitions and user area
• Goal: Mirror (duplicate) U‑Boot to boot0 and boot1 during factory flash

What happens today:

• Flashing the default .wic using uuu: U‑Boot is written to boot0 only; boot1 is empty afterwards.

What we already tried:

1. Extra entry in the .wks: added a second bootloader/rawcopy‑style entry intended to write to boot1. It didn’t produce the desired result (boot1 still empty).
2. Post‑processing script in the WIC pipeline: attempted to place U‑Boot at a fixed offset (e.g., +4 MiB) assuming it would reach boot1, but that still writes into the user area it seems, not the boot hardware partition, so it doesn’t achieve mirrored boot. (As far as I can see, WIC’s standard plugins like bootimg-partition/rawcopy address regular partitions; guidance for boot0/boot1 is unclear).
3. After boot on the target: From Linux we can dd to /dev/mmcblk0boot1 (after toggling force_ro) and then device boots from boot1 fine; so the silicon/board path is OK. But we must achieve this during factory flashing via .wic + uuu. (There are threads describing dd/offsets from Linux but not tied to WIC/UUU at factory time.)

What we’re looking for (requests):

1. Recommended way (NXP‑supported) to populate U‑Boot into boot0 and boot1 during factory flashing, ideally using:
   • A WIC plugin/usage example to target boot0/boot1 directly, or
   • A UUU script snippet that writes the same U‑Boot binary to both boot partitions (if WIC cannot directly address boot partitions). (Related discussions suggest mfgtools/uuu typically writes only the first boot partition unless customized—confirmation and an example would help a lot.
2. Sample .wks (or wic post‑process hook) that NXP recommends for i.MX95 modules to handle boot0 + boot1 mirroring.
3. Field upgrade best‑practices on iMX95 for U‑Boot A/B: Is there a NXP guide for bootloader redundancy with boot0/boot1, and switching via mmc partconf/bootbus safely from U‑Boot? (U‑Boot’s mmc docs cover partconf, bootbus, a NXP‑specific example would be great for uboot upgrade on field.)

[kawateb265]

You can refer to i.MX93 eMMC Secondary Boot. The script there is for burning eMMC boot0 and boot1. This part is the same for iMX95 and iMX93.

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/iMX-secondary-boot-collection/ta-p/19169...

i.MX93_emmc_boot_part_secondary_boot.uuu

uuu_version 1.2.39

SDPS: boot -f imx-boot-imx93-11x11-lpddr4x-evk-sd.bin-flash_singleboot-LF_v6.6.3_1.0.0
SDPV: delay 1000
SDPV: write -f imx-boot-imx93-11x11-lpddr4x-evk-sd.bin-flash_singleboot-LF_v6.6.3_1.0.0 -skipspl
SDPV: jump

#FB: ucmd setenv emmc_dev 1 
FB: ucmd setenv part 1 
FB: ucmd setenv boot_offset 0x0 
FB: ucmd setenv fastboot_dev mmc 
FB: ucmd setenv mmcdev ${emmc_dev}  
FB: ucmd if test ${part} != 7; then mmc dev ${emmc_dev} ${part}; else mmc dev ${emmc_dev}; fi
FB: ucmd setenv fastboot_buffer ${loadaddr}
FB: download -f imx-boot-imx93-11x11-lpddr4x-evk-sd.bin-flash_singleboot-LF_v6.1.55-2.2.0
#FB: download -f imx-boot-imx93-11x11-lpddr4x-evk-sd.bin-flash_singleboot-LF_v6.6.3_1.0.0 
FB: ucmd echo    ${fastboot_bytes}
FB: ucmd setexpr blks ${fastboot_bytes} / 0x200; setexpr blks ${blks} + 1
FB: ucmd mmc write ${loadaddr} ${boot_offset} ${blks}
# Secondary boot 
FB: ucmd setenv part 2 
FB: ucmd if test ${part} != 7; then mmc dev ${emmc_dev} ${part}; else mmc dev ${emmc_dev}; fi
#FB: download -f imx-boot-imx93-11x11-lpddr4x-evk-sd.bin-flash_singleboot-LF_v6.1.55-2.2.0
FB: download -f imx-boot-imx93-11x11-lpddr4x-evk-sd.bin-flash_singleboot-LF_v6.6.3_1.0.0 
FB: ucmd echo    ${fastboot_bytes}
FB: ucmd setexpr blks ${fastboot_bytes} / 0x200; setexpr blks ${blks} + 1
FB: ucmd mmc write ${loadaddr} ${boot_offset} ${blks}

FB: ucmd setenv part 1
FB: ucmd if env exists emmc_ack; then ; else setenv emmc_ack 0; fi;
FB: ucmd mmc partconf ${emmc_dev} ${emmc_ack} ${part} 0
FB: done

[kawateb265]

I recommend you refer to i.MX93 eMMC Secondary Boot. The mechanism of this part of iMX95 is the same as that of iMX93.

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/iMX-secondary-boot-collection/ta-p/19169...