The reference application is a dialogue box activity, and can be enabled through the Settings -> About tablet -> Additional
system Update menu. There are two buttons on the dialogue box:
• Upgrade: Performs full OTA.
• Diff Upgrade: Performs incremental OTA.
Click one button to update the Android platform. After update is complete, click the Reboot button on the dialogue box.
• This application uses the "ro.build.date.utc=1528987645" property to decide whether it can perform full OTA
or incremental OTA.
• local utc = $getprop ro.build.date.utc.
• remote utc = cat ${server_ota_folder}/build.prop | grep "ro.build.date.utc".
• remote diff utc = cat ${server_ota_folder}/build_diff.prop | grep "ro.build.date.utc".
• remote diff base utc = cat ${server_ota_folder}/build_diff.prop | grep "base.ro.build.date.utc"
(base.ro.build.date.utc should be added manually, which is the "ro.build.date.utc" value in PREVIOUS-
target_files.zip's system/build.prop).
• Full OTA condition:
— local utc < remote utc
• Incremental OTA condition:
— local utc = remote diff base utc
— local utc < remote diff utc
NOTE
The OTA package includes the DTBO image, which stores the board's DTB. There may be many DTS for one
board. For example, in ${MY_ANDROID}/device/fsl/imx8m/evk_8mn/BoardConfig.mk:
TARGET_BOARD_DTS_CONFIG := imx8mn:fsl-imx8mn-ddr4-evk-trusty.dtb
TARGET_BOARD_DTS_= imx8mn-mipi-panel:fsl-imx8mn-ddr4-evk-rm67191.dtb
TARGET_BOARD_DTS_= imx8mn-rpmsg:fsl-imx8mn-ddr4-evk-rpmsg.dtb
There is one variable to specify which dtbo image is stored in the OTA package:
BOARD_PREBUILT_DTBOIMAGE := out/target/product/evk_8mn/dtbo-imx8mn.img
Therefore, the default OTA package can only be applied for i.MX 8M Nano EVK with single MIPI-to-HDMI display.
To generate the OTA package for i.MX 8M Nano EVK with MIPI panel display, modify this
BOARD_PREBUILT_DTBOIMAGE as follows:
BOARD_PREBUILT_DTBOIMAGE := out/target/product/evk_8mn/dtbo-imx8mn-mipi-
panel.img
For detailed information about A/B OTA updates, see
https://source.android.com/devices/tech/ota/ab/
NOTE
8 Customized Configuration
8.1 How to change boot command line in boot.img
After boot.img is used, the default kernel boot command line is stored inside the image. It packages together during android build.
You can change this by changing BOARD_KERNEL_CMDLINE's definition in BoardConfig.mk file under
${MY_ANDROID}/
device/fsl
.
NXP Semiconductors
Customized Configuration
Android
™
User's Guide, Rev. P9.0.0_2.3.2, 6 March 2020
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