Debian on Dell Kace M300

root@m300-sid:/boot# fw_printenv
baudrate=115200
bootcmd=run bootcmd_uenv; run scan_disk; run set_bootargs; run bootcmd_exec; reset
bootcmd_exec=if run load_uimage; then; if run load_initrd; then if run load_dtb; then bootm $load_uimage_addr $load_initrd_addr $load_dtb_addr; else bootm $load_uimage_addr $load_initrd_addr; fi; else if run load_dtb; then bootm $load_uimage_addr - $load_dtb_addr; else bootm $load_uimage_addr; fi; fi; fi
bootcmd_uenv=run uenv_load; if test $uenv_loaded -eq 1; then run uenv_import; fi
bootdelay=10
bootdev=usb
console=ttyS0,115200
device=0:1
devices=usb sata
disks=0 1 2 3
dtb_file=/boot/dts/kirkwood-m300.dtb
if_netconsole=ping $serverip
initrd_high=0x40000000
load_dtb=echo loading DTB $dtb_file ...; load $bootdev $device $load_dtb_addr $dtb_file
load_dtb_addr=0x1c00000
load_initrd=echo loading uInitrd ...; load $bootdev $device $load_initrd_addr /boot/uInitrd
load_initrd_addr=0x2100000
load_uimage=echo loading uImage ...; load $bootdev $device $load_uimage_addr /boot/uImage
load_uimage_addr=0x800000
mtdparts=mtdparts=spi0.0:0x7f000@0(uboot),0x1000@0x7f000(u-boot-env)
preboot_nc=run if_netconsole start_netconsole
scan_disk=echo running scan_disk ...; scan_done=0; setenv scan_usb "usb reset; sleep 1; usb reset";  setenv scan_sata "sata init";  setenv scan_mmc "mmc rescan"; for dev in $devices; do if test $scan_done -eq 0; then echo Scan device $dev; run scan_$dev; for disknum in $disks; do if test $scan_done -eq 0; then echo device $dev $disknum:1; if load $dev $disknum:1 $load_uimage_addr /boot/uImage 1; then scan_done=1; echo Found bootable drive on $dev $disknum; setenv device $disknum:1; setenv bootdev $dev; fi; fi; done; fi; done
set_bootargs=setenv bootargs console=ttyS0,115200 root=LABEL=rootfs rootdelay=10 $mtdparts $custom_params
start_netconsole=setenv ncip $serverip; setenv bootdelay 10; setenv stdin nc; setenv stdout nc; setenv stderr nc; version;
stderr=serial
stdin=serial
stdout=serial
uenv_addr=0x810000
uenv_import=echo importing envs ...; env import -t $uenv_addr $filesize
uenv_init_devices=echo Initializing devices...; setenv init_usb "usb reset; sleep 1; usb reset"; setenv init_sata sata init;  setenv init_mmc mmc rescan; for devtype in $devices; do run init_$devtype; done;
uenv_load=run uenv_init_devices; setenv uenv_loaded 0; for devtype in $devices; do for disknum in $disks; do if test $uenv_loaded -eq 0; then setenv device_type $devtype; setenv disk_number $disknum; run uenv_read; fi; done; done;
uenv_read=echo Loading envs from $device_type $disk_number...; if load $device_type  $disk_number:1 $uenv_addr /boot/uEnv.txt; then setenv uenv_loaded 1; echo ... envs loaded; fi
usb_ready_retry=15
root@m300-sid:/boot#

U-Boot 2022.04-tld-1 (Mar 20 2022 - 18:15:15 -0700)
Dell KACE M300

[    7.840186][    T1] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on
unknown-block(0,0) ]---