If you flashed TP-Link's firmware image as is, you've got a soft-brick now. Their firmware image uses a custom format, and cannot be written directly to flash (which is what sysupgrade does). You would need to build tplink-safeloader from the OpenWrt sources to convert a TP-Link firmware file into a valid OpenWrt firmware file.
I'm not entirely sure anymore, but I think this device will launch a failsafe web server at the default address (192.168.1.1) if it fails to boot. This failsafe page should accept TP-Link images.
Good news, my friends! Finally I was able to send the original Tplink firmware via tftp by configuring the network card with IP 192.168.1.100.
Now I waiting to the led change from light green to dark green. For now, no wireless network from EAP.
EDIT: ok, ping for 192.168.1.1 works and now I get the page for send the firmware via browser on 192.168.1.1.
EDIT2: ok, send two times the firmware via failsafe web server but for some reason the device doesn't reboot and still in failsafe mode, even with "firmware upgrade success".
I'll try again with tftp method.
EDIT3: well, the problem persist with the tftp method. Any advices?
It seems likely the failsafe page also does signature verification on the firmware image. The OpenWrt factory image doesn't actually have a valid signature, so this would always fail.
When accessing the Tp Link recovery page to flash the factory firmware, after flash nothing happens. Upon restart, the device remains in recovery mode. Still giving me a 169.xx IP.
Telnet isn't normally available on this device, unless you find a way to start it as root (I haven't)
If the IP address of your computer/smartphone is 169.254.x.y address, then this is a link-local address, and is assigned by the operating system itself because there is no DHCP server available. Like you noted earlier, you need to assign yourself another address in the 192.168.1.0/24 subnet to be able to access the failsafe page.
That being said, it is still odd that even the failsafe page fails to restore the device to a working state.
The device is an access point with no DHCP server normally. It would not normally be the case that you could connect a laptop and get a dhcp response. After reflashing factory firmware, @bkdwt should follow instructions from factory installation manual to configure the device... Which I think means connecting via wireless! Or at a minimum, setting a static IP and connecting on an appropriate default IP network.
The device is inoperative and only provides an IP 169.xx. If I set the network interface to 192.168.1.100 I can only access the recovery interface, which in the end is of no use.
Now I'm trying to flash the firmware again via tftp, but it's giving an error:
Connection received from 192.168.1.1 on port 2774 [15/02 14:02:39.616]
Read request for file <EAP245v3_up.bin>. Mode octet [15/02 14:02:39.616]
OACK: <timeout=5,> [15/02 14:02:39.616]
Using local port 54885 [15/02 14:02:39.616]
TIMEOUT waiting for Ack block #4 [15/02 14:03:04.665]
This is fuc**** annoying. I already contacted the TP-Link support and I'll send this device to RMA. This AP is really broken for now.
the device doesn't provide this... your laptop just "decides" to put that there when it's unable to put anything else via DHCP. I want to clarify that so maybe you aren't under the wrong impression, it might help you in your debugging.
It's kind of surprising that the recovery interface and/or the TFTP don't work. I've generally had very good results with TP-link recovery. Perhaps try using an older version of the TP-Link factory firmware, perhaps the recovery thing doesn't work with the latest versions? (in particular they changed their firmware to the SDN version relatively recently, the 4.x series, try flashing a 3.x series firmware)
