I definitely need a fix before dark, but I’ll wait for the big guns to pick up this issue. 
I updated while on holiday 
I will not update when away from home again, hehe.
Does anyone have suggestions for remote recovery?
Flashing the firmware via PC and the webpage listed above worked for me.
Next time I won’t be that quick to upgrade any critical firmware.
In your case I would wait some. I’m sure the devs will come up with a cunning plan.
If not, I would suggest trying @mennzo’s option.
Yeah, this is a big lesson for me. I have OCD about updates, but I need to hold off on hitting that button and come here to check if there are any issues first!
My zbt2 failed, because I forgot to stop zigbee2mqtt.
Then it failed again, even after restarting HAOS (with ztm disabled on startup).
Finally, I did a full power off, un/replugged ztb2 usb, powered back up haos, and finally the fw was able to update.
Restarted z2m, and everything seems to be back up again.
TLDR;
- if you are using z2m, temporarily stop and disable on startup
- do a full power off, then restart
- when haos/HA is full running, re-try the fw update
My skyconnect/thread mode updated without issue (before I attempted zbt2)
good luck
2 Likes
Did the network address of the ZBT-2 stay the same? So, no need to re-connect the Zigbee devices?
In my case, everything is back to normal after flashing back 7.4.4.6 using Install Firmware – Device Toolbox
I just went for it, and it worked! Thanks to daredevils @mennzo and @Saoshen who risked it all and came up with a solution. 
1 Like
I did not experience any zigbee device issues, everything so far appears to be working as before.
That’s interesting, and suggests a timing issue with the upgrade code.
I didn’t stop ZHA, but the Zigbee firmware updated fine.
I wonder if the update code handles Z2M differently from ZHA?
Yes, zha is directly supported by HA, however z2m is an addon, so unfortunately anytime there is a zbt firmware update, z2m must be manually stopped.
For folks having used z2m awhile, they may have already had this issue, needing to stop z2m before doing a firmware update.
Basically, the device only supports one connection, so z2m must be stopped before the firmware updater can communicate with the device.
ZHA seems to automagically handle the communication to allow the firmware to update without manually stopping anything.
If one is already using ZHA and having update issues, the ‘full power off and restart’ suggestion still stands.
3 Likes
Stupidly I did the zbt-2 update tonight on two units one running zigbee the other Thread and both are down. I tried updating with my computer then reconnecting but no joy. Have plugged the old zigbee dongle in to get everything working.
Ran into the same issue with a Home Assistant Yellow. Is there any way to flash that one back to 7.4.4.6?
So, what is the best way to do this firmware update?
Running HAOS 17.1, bare metal, RPi5 + ssd, ZHA, HA 2026.2.3
Which one?
Zigbee or OpenThread?
ZHA or Z2M?
ZBT-2 or Yellow?
They are all different, and the combinations are covered in the thread above.
Sorry, I thought I was clear 
I am talking about Zigbee mode, ZHA, ZBT-2.
HAOS 17.1 running bare metal on RPi5
The Zigbee ZBT-2 upgrade “just worked” for me (ZHA+HAOS+RPi5+SSD) as the firmware upgrade can interrupt the Zigbee ZHA integration connection to the ZBT-2 (Z2M needs to be manually stopped).
If this fails, follow:
For Zigbee:
zbt2_zigbee_ncp_7.5.1.0_None.gbl
1 Like
Thank you FloatingBoater,
I am a little bit afraid about this procedure, I have bricked a Skyconnect ZBT-1 with this exact way, maybe because I am with Macbook silicon and Chrome?
I bought the ZBT-2 after that
Wow, what a lot of extreme remedies given here.
I’m using ZHA. I skipped 2026.2.0 and did the 2026.2.3 upgrade. Took a couple of goes before i realised the ZBT-2 firmware 7.5.1.0 update had failed. Rebooting the HA server didn’t help.
Finally looked on github issues and found this
Disabled ZHA, power cycled the ZBT-2 device and enabled ZHA …
ZBT-2 started with new firmware, and HA is using 2026.2.3
Most importantly, my zigbee is back.