GL-MT6000 unable to flash firmware

[rwalli]

Im unable to flash any firmware on MT6000: No space left on device.
Any suggestions?

Additional info

ubus call system board
{
"kernel": "6.12.71",
"hostname": "sz2",
"system": "ARMv8 Processor rev 4",
"model": "GL.iNet GL-MT6000",
"board_name": "glinet,gl-mt6000",
"rootfs_type": "squashfs",
"release": {
"distribution": "OpenWrt",
"version": "25.12.0",
"firmware_url": "https://downloads.openwrt.org/",
"revision": "r32713-f919e7899d",
"target": "mediatek/filogic",
"description": "OpenWrt 25.12.0 r32713-f919e7899d",
"builddate": "1772496855"
}
}
/tmp#sha256sum openwrt-25.12.1-mediatek-filogic-glinet_gl-mt6000-squashfs-sysupgrade.bin
b77939004588e4a44c6b71ef2cfdf6e6c921c4a88d7c53a1104fd6dcbb332d97 openwrt-25.12.1-mediatek-filogic-glinet_gl-mt6000-squashfs-sysupgrade.bin
/tmp#df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 12.3M 12.3M 0 100% /rom
tmpfs 493.2M 50.7M 442.5M 10% /tmp
/dev/loop0 7.2G 195.9M 7.0G 3% /overlay
overlayfs:/overlay 7.2G 195.9M 7.0G 3% /
tmpfs 512.0K 512.0K 0 100% /dev
/tmp#sysupgrade -T -n /tmp/openwrt-25.12.1-mediatek-filogic-glinet_gl-mt6000-squashfs-sysupgrade.bin
verifying sysupgrade tar file integrity
tar: write error: No space left on device
corrupted sysupgrade tar file
Image check failed.

[frollic]

@rwalli

No space left on device

Delete.... something?

You filled it, not us.

[rwalli]

@frollic

Delete.... something?

Do you think that's sound advice with 7G free on /overlay and over 400Mb on /tmp?

[rwalli]

fixed it.

if anyone is interested

error came from "/lib/upgrade/nand.sh" included from sysupgrade

nand_verify_tar_file() {
local file="$1"
local cmd="$2"

    echo "verifying sysupgrade tar file integrity"                  
    if ! $cmd < "$file" | tar xOf - > /dev/null; then     
            echo "corrupted sysupgrade tar file"          
            return 1                                      
    fi                                                                                         

}

where /dev/null was the problem (dont know why - rebooting did not help)

ls -la /dev/null
-rw-r--r-- 1 root root 0 Mar 20 21:53 /dev/null

fixed it with:

mknod -m 666 /dev/null c 1 3

flashing now worked and /dev/null looks better after flashing:

crw-rw-rw- 1 root root 1, 3 Jan 1 1970 /dev/null

[efahl]

@rwalli

where /dev/null was the problem (dont know why - rebooting did not help)

That was a bug in adblock, fixed almost immediately, but it sneaked onto a few devices.

Adblock support thread

I think there's a problem with the new adb_errorlog pointing to /dev/null and wiping out /dev/null's special attributes. Restarting adblock causes the file to become "normal". If I enable adb_debug which changes adb_errorlog to something besides /dev/null, it doesn't clobber the file. This is before and after a restart: root@router:~# ls -l /dev/null; service adblock restart; sleep 5; ls -l /dev/null crw-rw-rw- 1 root root 1, 3 Mar 4 21:27 /dev/null -rw-r--r-- 1 root ro…

[rwalli]

You are right, adblock is installed.

Thank you for pointing this out.
It saved me some time because a already started to search for the reason.

BTW: It first occured in owut, and I didn't post in the owut-thread because i tracked it down to sysupgrade.
Now i see, that was a big mistake

[efahl]

@rwalli

It saved me some time because a already started to search for the reason.

Yup.

Must. Know. Root. Cause.