ZBT-Z2101AX bricked. No Recovery mod

[samo1]

I flashed wrong firmware on my ZBT-Z2101AX and then bricked it. Tried to enter in recovery mod by holding reset button but didn't help. Is there other way to save the router?

[BillA]

I flashed wrong firmware on my ZBT-Z2101AX and then bricked it. Tried to enter in recovery mod by holding reset button but didn't help. Is there other way to save the router?

If you cannot enter flashing mode via the reset+power combination, then you could try flashing it using the TFTP or Command Line SysUpgrade/MTD methods below. If all else fails, the last resort is using the RX/TX headers on the main board.


*** TFTP flashing ***

Some routers don't have a Recovery GUI but instead use a method called TFTP to load and flash an image on the router.
These require a TFTP program on your computer like TFTP32 and some knowledge of what the router expects.
The router has a static IP Address like 192.168.2.119 and it expects the computer to also have a static IP like 192.168.2.88.
These IP Addresses vary according to the router involved.
In most cases the Firewall on the computer must be disabled while the upload and flash procedure takes place.
The router expects the firmware file to be named "firmware.file" so it can ask the TFTP program for that file by name.

To flash this way do the following.
1. place the properly named firmware file in the same directory as the TFTP program and start it.
2. Unplug the router and hold in the reset button.
3. Plug in the power while still holding in the reset button.
4. Wait until you see the TFTP program start to upload the firmware file and then
release the reset button.

The firmware file will be uploaded to the router and it will be flashed to it then rebooted.


*** Command line flashing ***

These methods can be used if you can get Telnet or SSH access to a router.
There are two command line methods that can be used to flash a router.
Which one is used depends on what packages are available on the factory firmware and how the firmware is laid out.

SysUpgrade method

If the factory firmware is based on a version of OpenWRT or is Linux based it should have a package called sysupgrade available.
You must either copy the firmware file over to the /tmp folder, or if the factory firmware supports it, flash it from a USB flash drive.
Files can be copied to the router using WinSCP if you have SSH access.
Using Telnet copy the file to a USB flash drive, plug it into the router and execute the following commands.

mkdir /mnt
mount /dev/sda1 /mnt

This will mount the USB flash drive and make it available for use.
At this point the firmware file will be at either /tmp/firmware.file or /mnt/firmware.file depending on the method used.

You can test if the flash will work via the following command.

sysupgrade –test /tmp/firmware.file

You can do the actual flashing via the following command.

sysupgrade /tmp/firmware.file

The router will reboot after this and run the new firmware.
If you find that the sysupgrade test fails but you know the firmware will work then execute the following command.

sysupgrade –force /tmp/firmware.file

This will force the firmware to be flashed even if it fails the test.
This is very dangerous and can brick your router.


MTD method

The other method of flashing involves a package called mtd which will copy files into partitions on the router.
This is not always available and can be used only in certain circumstances.
First, execute the following command to list the mtd partitions.

cat /proc/mtd
The output from this will look similar to this.
dev: size erasesize name
mtd0: 00030000 00010000 "u-boot"
mtd1: 00010000 00010000 "u-boot-env"
mtd2: 00010000 00010000 "factory"
mtd3: 00fb0000 00010000 "firmware"
mtd4: 00255bad 00010000 "kernel"
mtd5: 00d5a453 00010000 "rootfs"
mtd6: 00300000 00010000 "rootfs_data"

If you do not see a partition named "firmware", then do not proceed any farther.
Look for is the mtd block associated with the firmware partition.
In this case it's mtd3 but will vary from router to router.
As with the sysupgrade method, the firmware file must either be copied to the /tmp folder or use a USB flash drive and mounted.
To flash the firmware partition with "firmware.file", execute the following command.

mtd -r write /tmp/firmware.file

The partition will be flashed to the firmware file and the router will reboot.
Again this is very dangerous and can brick your router.
Command line flashing is normally a last resort and should not be attempted by unskilled users.