Reverting D-Link DAP-2610 to OEM firmware

[BarbaPin]

Hi team, what is the suggested way to re-install OEM firmware on this device?
Could not find any info on the specific hardware OpenWRT docs, nor for the generic DAP family.
Trying to update firmware with LUCI on the device, uploading the D-Link official release, it throws an error message (see below), so I'd be glad if anybody can suggest before I brick the device
Also need to know if the .zip file from D-Link should be used, or just the DAP-2610_firmware_v2.06r089.bin inside it.
Thanks!

[frollic]

https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=52b8c7a8928ccdc80436c76955f237960ea3bf1f

[BarbaPin]

Thanks so much @frollic for your suggestion.
So the command to use would be..

Return to stock D-Link firmware
===============================
Partition layout is preserved, and it is possible to return to the stock
firmware simply by downloading it from D-Link and writing it to the
firmware partition.

    # mtd -r write dap2610-firmware.bin firmware

So I did the following (maybe useful for others....):

1. downloaded latest fw version from D-Link site (it's v2.06_20211028 in this specific case) to my Linux PC
2. copied the fw to the DAP via scp to the /tmp directory of the DAP (no space under /home apparently)
3. then ssh into the DAP, moved to /tmp and issued

root@DLINK-DAP2610:/tmp# mtd -r write DAP-2610_firmware_v2.06r089.bin firmware

mtd flashed the firmware (apparently) and rebooted the DAP.

I could then reach the DAP with 192.168.0.50 as explained here (see paragraph "Flashing"):

D-Link DAP Series of Business Access Points

but with my great surprise, I got the Emergency Web Server, not the D-Link web page
So again I flashed the D-Link firmware... it took a few minutes (see screenshot), but then no joy :
the DAP keeps showing the Emergency Web Server after the fw is flashed, no matter how many times I do this.

Any suggestion?

PS: in case it does matter, the DAP was installed with 22.03.5, factory + sysupgrade (not just factory)

[BarbaPin]

A bit of luck... re-flashing the FACTORY OpenWrt did bring back the DAP with the default Ip 192.168.1.1.
Uhmmm... the hostname is OpenWrt, but the password was kept (it's not empty)... very weird.
Will try to do some other testing....

[BarbaPin]

Did full reset of the config with LuCI and now no password is required with FACTIRY OpenWrt installation.
No joy with the D-Link 2.06 firmware (the DAP keeps booting into Emergency Web Server).
Wonder if I should try with an older D-link firmware or if (most likely) the file system got corrupted when the SYSUPGRADE OpenWrt was installed

Any suggestion welcome , as well as any additional info on the DAP.

[Djfe]

Maybe try accessing the emergency web server via chromium (Chrome etc.) instead of Firefox.
Some newer D-Link models (DAP-X1860) only work correctly with Chromium. Maybe this older one as well

or if (most likely) the file system got corrupted

I don't believe that to be possible actually.

Sure, try installing older firmwares, that could work
https://support.dlink.com/productinfo.aspx?m=DAP-2610

And if it doesn't you can still return to OpenWrt
There's definitely some way to return to stock os, even if you fail at the moment. I don't own the hw myself so can only guess

[BarbaPin]

Thanks @Djfe . Downloaded version 2.01 (october 2020, probably the one tested by developers during commit), installed it with mtd and it shows up

So at least we know which OEM release shall be used to revert back the firmware (maybe documentation could be amended?).

Unfortunately the DAP is working only on 5Ghz, not 2.4Ghz, so I really think radio0 is bad.
D-Link log log is not showing meaningful info

Accessing the DAP via SSH was frustrating.... very customized shell, no way to search for logs... at least for me.

So in the end:

1. we know that DAP can effectively work on 2.4 thanks to @Klingon which confirmed this for his DAP
2. we know how to revert back to D-Link firmware 2.01 (at least it worked for me)
3. my DAP seems to have problems with radio0 2.4Ghz, although they do not show in log (neither with D-Link firmware, nor with OperWRT).

I am moving to a working TP-Link EAP225 now

Thanks a lot to @Klingon and @Djfe for the precious suggestions!