Editing Devicetree?

[nottheoilrig]

Two questions:

1. If I want to edit my pocket’s Devicetree (e.g. edit generic USB properties) I think the source file to edit (for i.MX8MPlus CPU module) is imx8mp-mnt-pocket-reform.dts · main · Reform / MNT Reform i.MX8MPlus U-Boot Build · GitLab?
2. I edited that file and built imx8mp-mnt-pocket-reform-flash.bin … now how do I test it?

For instructions I searched:

• The System Boot section of the operator handbook
• The MNT Reform i.MX8MPlus U-Boot Build project
• The reform-system-image project

If I understand mkimage.sh, on my SD card I need to overwrite /boot/flash.bin with my new imx8mp-mnt-pocket-reform-flash.bin … is that right? Sorry I’m new to bootloader …

[josch]

@nottheoilrig

I think the source file to edit (for i.MX8MPlus CPU module) is imx8mp-mnt-pocket-reform.dts · main · Reform / MNT Reform i.MX8MPlus U-Boot Build · GitLab?

No, that is the device tree for u-boot, not the one that Linux uses. The one that Linux uses is here: linux/imx8mp-mnt-pocket-reform.dts · main · Reform / reform-debian-packages · GitLab

You can copy that file to your git repo of Linux and then build it as usual and then copy it to /boot/dtbs/$(uname -r)/freescale/imx8mp-mnt-pocket-reform.dtb. This is where it will get picked up by u-boot. You do not need to rebuild u-boot or flash a modified version of your bootloader.

@nottheoilrig

If I understand mkimage.sh, on my SD card I need to overwrite /boot/flash.bin with my new imx8mp-mnt-pocket-reform-flash.bin

No, /boot/flash.bin is just a file containing u-boot and not used in the boot process. You do not need to modify u-boot.