i.MX 93 EVK: Cannot Access LD Mode

[HansH]

I am working on the i.MX93EVK. I am trying to switch the board to a low-power LD mode.  NXP application note AN13917 details different power modes (e.g., OD, ND, LD) and how to switch between them.  However, not all of the commands work.  I can get into OD and ND modes, but I cannot get into the low-power LD modes.  If I try to switch to LD mode, I get an invalid argument error (see bash output below).  I tried booting both NXP Linux L6.6.3 and L6.1.55.  Is there something I am missing?

root@imx93evk:~# echo 1 > /sys/devices/platform/imx93-lpm/mode
[ 2560.222108] System switching to ND mode...

root@imx93evk:~# echo 0 > /sys/devices/platform/imx93-lpm/mode

[ 2620.258231] System switching to OD mode...

root@imx93evk:~# echo 2 > /sys/devices/platform/imx93-lpm/mode

-sh: echo: write error: Invalid argument

root@imx93evk:~# echo 3 > /sys/devices/platform/imx93-lpm/mode

-sh: echo: write error: Invalid argument

[HansH · Accepted solution]

The problem was that I needed to boot with a special DTB file: "imx93-11x11-evk-ld.dtb".  In U-Boot, I ran "setenv fdtfile imx93-11x11-evk-ld.dtb" followed by "boot".  This fixed the issue for me.