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Diffstat (limited to 'Documentation/boards/imx/nxp-imx8mm-evk.rst')
| -rw-r--r-- | Documentation/boards/imx/nxp-imx8mm-evk.rst | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/Documentation/boards/imx/nxp-imx8mm-evk.rst b/Documentation/boards/imx/nxp-imx8mm-evk.rst index c3cd35ae38..aa70419139 100644 --- a/Documentation/boards/imx/nxp-imx8mm-evk.rst +++ b/Documentation/boards/imx/nxp-imx8mm-evk.rst @@ -69,3 +69,32 @@ board for serial download mode as printed on the PCB. You can start barebox with the imx-usb-loader tool that comes with barebox like this: ./scripts/imx/imx-usb-loader images/barebox-nxp-imx8mm-evk.img + +Installing barebox +================== + +When the EVK is strapped to boot from eMMC, the i.MX8M bootrom will +consult the eMMC ext_csd register to determine whether to boot +from the active eMMC boot partition or from the user area. + +The same barebox image written to the start of the SD-Card can +be written to the start of the eMMC user area. Power-fail-safe +installation to the eMMC boot partition requires special handling: + + - The barebox image must be written to the inactive boot partition, + then afterwards, the newly written boot partition is activated + (This is controlled by the barebox ``mmcX.boot`` variable). + +The following steps are required to write the image to the QSPI NOR flash: + + - The 32KiB preamble MMC preamble must be stripped. + + - The QSPI NOR partition ``barebox`` must be erased before the stripped + image is written. The erase size depends on the stripped image size but + always start at offset 0. + + - Write the stripped barebox image to the QSPI NOR partition ``barebox`` + at offset 0. + +The ``barebox_update`` command takes care of this and need just be +supplied a barebox image as argument. |