U-Boot Debug Tips

  1. After U-boot upgrade, Kernel stops booting

Check if one of the cases below applies:

  • Not resetting U-boot environment variables after upgrading/downgrading u-boot version

    From release to release, some of the u-boot environment variables may be changed. To guarantee the environment variables are correctly matching the version used, it is required to reset the u-boot environment variables When upgrading/downgrading u-boot version. When booting up a different version of u-boot, the u-boot boot process can be interruptted by hitting any key to get the u-boot prompt. Then, the following command needs to issue to reset the u-boot environment variables.

    # env default -f -a
    # saveenv
  • Mix-matching U-boot and Linux kernel version

    There are times that users mix-match u-boot and kernel version from different SDK releases. It probably is fine in most cases, but TI recommends the u-boot and kernel are from the same SDK release. From release to release, the u-boot environemt variables may change, including load addresses, kernel image format, etc. Any of the incompatibility of these changes between u-boot and kernel will cause boot issues. Therefore, when u-boot is upgraded or downgreaded, a reset of the u-boot environment variables is requried. Please see how to reset u-boot environment variables in previous bullet.

  1. Not able to boot U-boot with different boot mode

  • Check if the instruction for supported u-boot boot modes is followed.

Please follow instructions in U-boot User’s Guide

Different boot modes ues diferent image formats. They are:
  • u-boot-spi.gph

  • rootfs-image.ubi

  • u-boot.bin

  • MLO

For Keystone-2 platforms, U-boot can also be brought up using CCS. The step-by-step instruction on booting up u-boot with one of the boot modes or using CCS are documented in <Processor_SDK_install_dir>/board-support/u-boot-<ver>/board/ti/ks2_evm/README file.