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Overview

This page provides an overview of U-Boot (Universal Boot Loader) support in Qualcomm Linux (QLI) software.

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Supported SoCs

SoC NameSupported?Storage
QCS6490YesUFS
IQ-9075YesUFS
IQ-615YeseMMC
IQ-8275No

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Build U-Boot image

This section describes how to build the U-Boot binary as part of the QLI 2.0 software.

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1. From Qualcomm Linux GitHub repository

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Prerequisites

Before proceeding with the build steps, do the following:
  1. Install following package on your local machine: 
    sudo apt install libgnutls28-dev
  2. Download and extract the Arm GNU Toolchain: 
    cd ~  # or your preferred location
wget https://developer.arm.com/-/media/Files/downloads/gnu/14.2.rel1/binrel/arm-gnu-toolchain-14.2.rel1-x86_64-aarch64-none-linux-gnu.tar.xz
tar -xf arm-gnu-toolchain-14.2.rel1-x86_64-aarch64-none-linux-gnu.tar.xz
    • This creates the toolchain directory at ~/arm-gnu-toolchain-14.2.rel1-x86_64-aarch64-none-linux-gnu/. If you extract it to a different location, adjust the paths in the build commands accordingly.
    • Install the toolchain on an x86 64-bit host computer only.
    • For other versions, visit Arm GNU Toolchain Downloads.
  3. Download the qtestsign utility: 
    cd ~  # or your preferred location
git clone https://github.com/msm8916-mainline/qtestsign qtestsign

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Build steps

  1. Download the U-Boot repository from Qualcomm Linux GitHub to your local workspace and move to the u-boot folder: 
    git clone https://github.com/qualcomm-linux/u-boot.git
  2. Switch the branch: 
    git switch qcom-next
  3. Check out the SRC REV for the QLI 2.0 release: 
    git checkout 5a77d4670d8084ada24a2735dda75788ed5ce925
  4. Configure the build for your platform. This command creates the required configuration files in the .output directory. Choose the command based on your platform:
    SoCCommand
    QCS6490make O=.output qcs6490_defconfig
    IQ-9075make O=.output qcom_lemans_defconfig
    IQ-615make O=.output qcom_qcs615_defconfig
  5. Build U-Boot using the cross-compile toolchain: 
    make -j8 CROSS_COMPILE=~/arm-gnu-toolchain-14.2.rel1-x86_64-aarch64-none-linux-gnu/bin/aarch64-none-linux-gnu- O=.output
    Replace ~/arm-gnu-toolchain-14.2.rel1-x86_64-aarch64-none-linux-gnu/ with your actual toolchain installation path if you extracted it to a different location.
    Expected result:
    • The U-Boot build completes without errors.
    • The u-boot.elf file is available in the .output directory.

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Convert u-boot.elf to u-boot.mbn

This command generates the signed u-boot.mbn file required for flashing: 
python ~/qtestsign/qtestsign.py -v6 aboot -o .output/u-boot.mbn .output/u-boot.elf
Replace ~/qtestsign/ with your actual qtestsign installation path if you cloned it to a different location.

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Enabling Kernel-Based Virtual Machine (KVM)

To enable KVM mode in U-Boot, update the defconfig file for your target platform by adding the following configuration options: 
CONFIG_ENABLE_ARM_SOC_BOOT0_HOOK=y
CONFIG_QCOM_EL2_GUNYAH_EXIT_SUPPORT=y
After modifying the defconfig, rebuild U-Boot following the steps in Build U-Boot image.

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2. Using Yocto build

Follow the instructions on the Build Qualcomm Linux using Yocto page with the following modifications:
  • To generate the U-Boot binary, append :meta-qcom/ci/u-boot-qcom.yml KAS fragment to the build command in step 3 of “Build a BSP image”.
  • In the build artifacts folder, the final U-Boot binary is generated as uefi.elf in the <workspace-dir>/build/tmp/deploy/images/<MACHINE>/<IMAGE>-<MACHINE>.rootfs.qcomflash/ directory.
Kernel-Based Virtual Machine (KVM) is enabled by default for KVM-supported targets (IQ-9075 and IQ-615) in the Yocto build. The following configurations are added by default when building U-Boot for these targets:
CONFIG_ENABLE_ARM_SOC_BOOT0_HOOK=y
CONFIG_QCOM_EL2_GUNYAH_EXIT_SUPPORT=y

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Flash U-Boot image

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Using Qualcomm tools

Follow the build flashing instructions to flash the U-Boot binary along with the QLI 2.0 build as described in Flash software images.

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Using Fastboot

  1. Enter fastboot mode using one of the following methods:
    • From kernel: 
      adb shell reboot bootloader
    • From U-Boot CLI: 
      run fastboot
  2. Flash the desired image from the host. For example, to flash the U-Boot image: 
    fastboot flash uefi_a u-boot.mbn
  3. Restart the device: 
    fastboot reboot

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Supported U-Boot commands

The following table lists some of the key U-Boot commands available on the supported platforms. These commands cover boot management, environment management, storage access, and hardware peripheral control. The available commands may vary depending on the platform support.
  • In QCS6490, Watchdog is used by the Hypervisor; therefore, Watchdog commands do not work for QCS6490.
CommandDescription
Boot
run bootcmdRun the default boot command sequence defined in bootcmd
bootefi bootmgrLoad and boot EFI payload based on BootOrder/BootXXXX variables
bootflow scan [-abeGl] [bdev]Scan for valid bootflows (-l list, -a all, -e errors, -b boot)
bootflow list [-e]List scanned bootflows (-e to include errors)
bootflow select [<num>|<name>]Select a bootflow by number or name
bootflow info [-ds]Show info on the current bootflow (-d dump bootflow)
bootflow bootBoot the current bootflow
bootdev list [-p]List all available boot devices (-p to probe)
bootdev info [-p]Show information about the current boot device (-p to probe)
General
printenvPrint environment variables
saveenvSave environment variables
versionPrint monitor, compiler, and linker version
run fastbootEnter fastboot mode and wait for fastboot command requests from the host machine
reset -edlEnter EDL (Emergency Download) mode
SCSI
scsi scanScan SCSI bus
scsi infoShow available SCSI devices
scsi device [dev]Show or set current device (dev should be 0, 1, 2, 3, 4, 5, …)
scsi part [dev]Print partition table of one or all SCSI devices
scsi read [addr] [blk#] [cnt]Read cnt blocks starting at block blk# to memory address addr
scsi write [addr] [blk#] [cnt]Write cnt blocks starting at block blk# from memory address addr
MMC
mmc listList available MMC devices
mmc infoShow current MMC device info
mmc dev [dev]Show or set current MMC device
mmc partPrint partition table of the current MMC device
mmc read [addr] [blk#] [cnt]Read cnt blocks from MMC starting at block blk# to memory address addr
mmc write [addr] [blk#] [cnt]Write cnt blocks to MMC starting at block blk# from memory address addr
Regulator
regulator listList UCLASS regulator devices
regulator dev [regulator-name]Show or set the operating regulator device
regulator infoPrint constraints info
regulator status [-a]Print operating status (for all with -a)
regulator value [val] [-f]Print or set voltage value in µV (force with -f)
regulator enableEnable the regulator output
regulator disableDisable the regulator output
Watchdog (WDT)
wdt listList available watchdog devices
wdt dev [devname]Show or set current watchdog device
wdt start <timeout_ms>Start the watchdog timer with the specified timeout in milliseconds
wdt stopStop the watchdog timer

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See also