Hey there, been using OpenWRT for a while on my U6 Plus. Yesterday I reflashed it via LuCi web interface but it went to soft-brick state. I successfully reflashed it with Unifi firmware and it worked (6.7.17), but there are leftover files after OpenWRT (version 25). If I follow strictly the official guide it reboots (looks like it was successful) but goes every time into the soft-brick state - every two seconds the LED ring flashes white.
What are possible solutions to reinstall OpenWRT? Try to remove the affected partitions?
IMHO, this is also the best way to restablish a baseline for OpenWrt installation. If the AP fails to boot OEM firmware then it will fail to boot OpenWrt too.
OpenWrt does not touch the emmc partition table on the U6+, so there is no need to mess with the partitions when going back to stock firmware. If you want to remove all traces of OpenWrt, then two successive OEM firmware installs should take care of that.
Thanks, with official firmware from Ubiquiti the AP works well, no problem with booting at all. Only after flashing OpenWRT it gets stuck. The UI firmware does not delete everything (tried 2 times in a row and the end was the same), there are eg. /etc and other files and folders left from OpenWrt installation.
Where do you see these files if OpenWRT gets stuck?
Installing the official firmware using tftp recovery will overwrite kernel0, but leave kernel1 (with the OpenWrt rootfs) intact. This is expected and documented on
Upgrading the official firmware from the offical firmware will however write to kernel1 and therefore overwrite the OpenWrt rootfs. I guess there still could be traces of it left after the end of the offical firmware. But I don't see what harm that does. If it is a problem, then you could add
dd if=/dev/zero of=/dev/mmcblk0p7
as a step 6b in the installation instructions. I.e. just before you write the OpenWrt kernel and rootfs to flash.
Yes, It is quite unusual. So let's get started.
I put the AP into tftp recovery mode (white-blue flashing) then I am able to successfully flash original Unifi firmware which works well.
The problem is that after flashing original Unifi firmware there are still many leftover files (traces) after OpenWrt. I assume that it is not correct. It should be completely wiped.
Then I proceed to new OpenWrt installation following the official guide, after repeating everything step by step the device reboots and it should (in theory) load OpenWrt firmware.
Then there is my second problem, it does not load the firmware but it goes to brick state when the main LED is every 2 seconds flashing white.
To sum up,
problem: AP after tftp flashing does not wipe everything from old OpenWrt installation
problem: OpenWrt fails to load after step by step correct installation and bricks the AP
Ahh, OK, then I understand. Yes, you are correct it is kernel1, I was thinking about how is this possible, but if it is well documented that would probably not be a problem.
I meant this could be a problem why OpenWrt failed to load after following the flashing guide on wiki. Now, I do not know what could cause the device to turn into brick state.
Did you solve the issue? I have a very similar problem. I can flash the original firmware (unifi) with the TFTP mode. This works. I can boot the device and log into it.
Doing so I followed the instruction to flash openwrt to the point.
Rebooting, I get error messages (via the serial interface) that the kernel signature could not be verified. After that it drops back into the TFTP mode (alternating off, whilte, blue blinking).
Strangely, this comes from a point where I have been able to run openwrt on the same device before, I misconfigured something, locked myself out and trying to get access again, I ended up in this loop.
I could see that this is a kernel0 kernel1 thing, but was not able to solve that riddle right now.
I tried different versions of openwrt (24 and 25) and different versions of the original firmware to start with (the one given in the openwrt wiki as well as the most recent one)
I also tried to add a step 6b by zeroing the partitions 6,7 and 8 before to make sure there is nothing left behind.
What puzzles me most is the message about the verification of the openwrt kernel, which fails and results in an error.
Having the serial interface, I can enter uboot-mode but couldn't find a way to boot e.g. from another partition.
Would be glad if you could solve your issue and give me some hints.
Hi torwag, I solved it partially, I thought I was the ONLY one who came across this issue but now we are probably two (Your behaves the same way as mine).
So, I successfully deleted the partitions (6 and 7) and I was able to flash latest Unifi firmware on it. That's all. I ended up with just simply adding it to Unifi OS server and using it as normal Ubnt AP.
Now I cannot install OpenWRT on it anymore.
If it helps in your progress, I tried following: (X means failed, OK means success)
Flashed any 2 versions of Ubnt firmware and used the default procedure to flash OWrt on it - X
Adopted and used with default Ubnt FW without any problems - OK
Installed OWrt using Ubnt TFTP method - X
Installed OWrt and (after it fails to boot) hold RESET button - X
NOT TESTED:
Flashing latest recommended FW on OWrt wiki - probably no longer available 2. Flashing 24.10 FW
Hope that helps,
thank you for reaching this topic,
Andy
EDIT: I failed to read the line where you mentioned testing 24 FW.
I didn't want to hijack your thread with my problem thus, I started an own.
Long story short, I found a much older unifi firmware flashed that via TFTP and from there I was able to flash OpenWRT.
You will find more details and the link to the firmware in that post. Maybe that helps if you want to give it another try... albeit... never change a running system
