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TMDS64GPEVM: U-Boot and GPT partition format

Jakub Grad
Intellectual 770 points

Part Number: TMDS64GPEVM
Other Parts Discussed in Thread: AM6442, TIGER

Hello

In our custom product based on AM6442 SoC we want to use GPT partition layout. We are using yocto with SDK 8 to generate the image. I have prepared wks file to generate proper .wic image with desired partition layout in GPT format. Here is that file:

bootloader --ptable gpt --append="rootfstype=ext4"
part /boot --source bootimg-efi --sourceparams="loader=grub-efi" --fstype=vfat --label boot --active --align 1024 --use-uuid --fixed-size 600M
part / --source rootfs --fstype=ext4 --mkfs-extraopts "-T default" --label SSC_SLOT_A --exclude-path tiger/ --fixed-size 4G --align 1024 --use-uuid
part --fstype=ext4 --mkfs-extraopts "-T default" --label SSC_SLOT_B --fixed-size 4G --align 1024 --use-uuid
part /tiger --source rootfs --fstype=ext4 --mkfs-extraopts "-T default" --label SSC_TIGER --fixed-size 8G --align 1024 --use-uuid
part /persistent --fstype=ext4 --mkfs-extraopts "-T default" --label SSC_PERSISTENT --fixed-size 10G --align 1024 --use-uuid
part /var/log --fstype=ext4 --mkfs-extraopts "-T default" --label SSC_LOG --size 1G --align 1024 --use-uuid

But unfortunately the image generated in that way does not boot - I didn't see any logs on my console. If --ptable msdos is set instead then the tispl,u-boot logs are showing and the image is booting. It is possible to somehow force bootloaders to work properly with GPT partition layout?

BR

Jakub

  • 0
    TI__Guru 70692 points

    Hi Jakub,

    Jakub Grad said:
    In our custom product based on AM6442 SoC we want to use GPT partition layout.

    ROM boot using the GPT scheme is not supported on current AM64x devices, so you'll need to stick to MBR. If you must use GPT in your product you could do the initial boot from a different boot media (like a SPI-type Flash), and then continue booting/using a media with GPT partition layout from thereon.

    Regards, Andreas

  • +1 in reply to Andreas Dannenberg
    TI__Guru 70692 points

    One variant of what I was hinting at would be the use of the eMMC boot mode. In this mode, your initial boot binaries (tiboot3.bin, etc.) would get loaded from the eMMC boot partition (boot0 or boot1), and the file system would get loaded from the UDA (User Data Area), for which you can use a GPT without any issues. The advantage here is you can use a single boot media, and have GPT.

    Regards, Andreas