[iMX8QXP] Error: "bootcmd_run" not defined; Unrecognized filesystem type

[roby1337]

Hello I'm having issues booting to my custom image.

My SD card was formatted with FAT32, and these were the image files I moved there:

user@rog:~$ ls /media/EBF7-ECC3/
image.json myos-image-colibri-imx8x.bootfs.tar.xz
imx-boot myos-image-colibri-imx8x.tar.xz
LA_OPT_NXP_SW.html toradexlinux.png
marketing.tar u-boot-initial-env-sd
prepare.sh wrapup.sh

Installed the image with Tezi 5.7.5+build.19 for Colibri iMX8X, and flashed the image with recovery mode as stated in the documentation.

When booting, I'm having these errors:
```
U-Boot 2020.04-0+git.1a13a90766f7 (Jan 31 2024 - 17:53:31 +0000)

CPU: NXP i.MX8QXP RevC A35 at 1200 MHz at 43C

DRAM: 2 GiB
MMC: FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from MMC... OK
In: serial
Out: serial
Err: serial
Model: Toradex Colibri iMX8 QuadXPlus 2GB Wi-Fi / BT IT V1.0D, Serial# 07329830

BuildInfo:
- SCFW 216a2c2e, SECO-FW 376e3c15, IMX-MKIMAGE 6745ccdc, ATF b0a00f2
- U-Boot 2020.04-0+git.1a13a90766f7

flash target is MMC:0
Net: eth0: ethernet@5b040000 [PRIME]
Fastboot: Normal
Normal Boot
Hit any key to stop autoboot: 0
switch to partitions #0, OK
mmc0(part 0) is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
973 bytes read in 19 ms (49.8 KiB/s)
## Executing script at 83200000
** Unrecognized filesystem type **
## Error: "bootcmd_run" not defined
SCRIPT FAILED: continuing...
```

My `image.json`:
```
{
"config_format": "4",
"autoinstall": false,
"name": "myos-image version 1.0-r0",
"description": "A console-only image with more full-featured Linux system functionality installed.",
"version": "3.1.32",
"release_date": "2024-03-13",
"u_boot_env": "u-boot-initial-env-sd",
"prepare_script": "prepare.sh",
"wrapup_script": "wrapup.sh",
"marketing": "marketing.tar",
"icon": "toradexlinux.png",
"supported_product_ids": [
"0038",
"0050",
"0051",
"0052"
],
"blockdevs": [
{
"name": "mmcblk0",
"partitions": [
{
"partition_size_nominal": 48,
"want_maximised": false,
"content": {
"label": "BOOT",
"filesystem_type": "FAT",
"mkfs_options": "",
"filename": "myos-image-colibri-imx8x.bootfs.tar.xz",
"uncompressed_size": 12.62890625
}
},
{
"partition_size_nominal": 512,
"want_maximised": true,
"content": {
"label": "RFS",
"filesystem_type": "ext4",
"mkfs_options": "-E nodiscard",
"filename": "myos-image-colibri-imx8x.tar.xz",
"uncompressed_size": 1222.00390625
}
}
]
},
{
"name": "mmcblk0boot0",
"erase": true,
"content": {
"filesystem_type": "raw",
"rawfiles": [
{
"filename": "imx-boot",
"dd_options": "seek=0"
}
]
}
}
]
}
```

`boot.scr` from `myos-image-colibri-imx8x.bootfs.tar.xz`:
```
# Copyright 2020 Toradex
#
# TorizonCore boot script.

if test -z "${altbootcmd}"
then
env set altbootcmd 'env set rollback 1; run bootcmd'
env save
fi

if test "${rollback}" = "1" && test "${upgrade_available}" = "1"
then
# Make sure to reset upgrade_available to avoid unnecessary wear
# Note this also makes rollback permanent. aktualizr will reset rollback
# when a new (hopefully better) update comes in.
env set upgrade_available 0
env save
fi

# save default U-Boot devicetree file to use in a rollback situation
env set fdtfile2 "${fdtfile}"

if test -n "${loadaddr}"
then
ext4load ${devtype} ${devnum}:1 ${loadaddr} /boot/loader/uEnv.txt; env import -t ${loadaddr} ${filesize}
else
ext4load ${devtype} ${devnum}:1 ${scriptaddr} /boot/loader/uEnv.txt; env import -t ${scriptaddr} ${filesize}
fi

run bootcmd_run
```

I suppose there is something wrong with the u-boot configuration?
Any idea where I can start looking & debugging in order to fix it?
I can provide more info, if needed.