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| -rw-r--r-- | doc/board/samsung/e850-96.rst | 85 |
1 files changed, 74 insertions, 11 deletions
diff --git a/doc/board/samsung/e850-96.rst b/doc/board/samsung/e850-96.rst index 0a7b6fc0c9d..b435fa8b353 100644 --- a/doc/board/samsung/e850-96.rst +++ b/doc/board/samsung/e850-96.rst @@ -43,17 +43,19 @@ Legend: BL31 in terms of ARM boot flow * ``LDFW``: Loadable Firmware -Build Procedure +Unbricking Note --------------- -.. warning:: - At the moment USB is not enabled in U-Boot for this board. Although eMMC is - enabled, you won't be able to flash images over USB (fastboot). So flashing - U-Boot binary **WILL** effectively brick your board. The ``dltool`` [8]_ can - be used then to perform USB boot and flash LittleKernel bootloader binary [7]_ - to unbrick and revive the board. Flashing U-Boot binary might be helpful for - developers or anybody who want to check current state of U-Boot enablement on - E850-96 (which is mostly serial console, eMMC and related blocks). +In case the board is bricked for some reason, the ``dltool`` [8]_ can be used to +unbrick and revive it. This tool performs USB boot, and uploads the LittleKernel +bootloader over USB, which is then being executed on the board. The loaded +bootloader further enters fastboot mode, so that the user can flash the +functional bootloader binary (U-Boot or LittleKernel [7]_) to eMMC using +``fastboot`` tool. Please read the ``dltool`` README file for more details about +the procedure. + +Build Procedure +--------------- Build U-Boot binary from source code (using AArch64 baremetal GCC toolchain): @@ -64,8 +66,9 @@ Build U-Boot binary from source code (using AArch64 baremetal GCC toolchain): make e850-96_defconfig make -Boot E850-96 board into fastboot mode as described in board software doc [9]_, -and flash U-Boot binary into ``bootloader`` eMMC partition: +The original E850-96 board is shipped with LittleKernel-based bootloader flashed +in eMMC. To replace it with U-Boot, boot into fastboot mode (as described in +the board software documentation [9]_), and flash U-Boot binary: .. prompt:: bash $ @@ -74,6 +77,66 @@ and flash U-Boot binary into ``bootloader`` eMMC partition: U-Boot will boot up to the shell. +Flashing +-------- + +User area of eMMC contains GPT partition table (either Linux or Android). Boot +Partition A (``mmc0boot0``) contains all firmware/bootloaders. Boot Partition +B (``mmc0boot1``) contains U-Boot environment. + +First make sure to format eMMC accordingly. Prepare the initial environment: + +.. prompt:: bash => + + env default -f -a + env save + +For Linux, just format eMMC using default ``$partitions`` definitions: + +.. prompt:: bash => + + gpt write mmc 0 $partitions + +For Android, use ``$partitions_android`` instead: + +.. prompt:: bash => + + setenv partitions_linux $partitions + setenv partitions $partitions_android + env save + gpt write mmc 0 $partitions + +In case of Linux, there are two partitions available: ``esp`` (EFI System +Partition) and ``rootfs``. It is recommended to use fastboot to flash images to +those partitions. Enter fastboot mode on your device: + +.. prompt:: bash => + + fastboot usb 0 + +And then flash the images: + +.. prompt:: bash $ + + fastboot flash esp esp.img + fastboot flash rootfs rootfs.img + +To update the firmware, it's easier to use DFU. Enter DFU mode on the board: + +.. prompt:: bash => + + dfu 0 mmc 0 + +To update U-Boot: + +.. prompt:: bash $ + + dfu-util -D u-boot.bin -a bootloader + +It's also possible to use fastboot to flash the whole ``mmc0boot0`` HW +partition, but it's not so straightforward, as one have to prepare the image for +the whole ``boot0`` partition containing all firmware binaries first. + References ---------- |