RT-AC88U Power LED blinking after reset. No restore possible

[PAPPL]

I forgot my Asus WebGUI password (Merlin firmware) and decided to reset my router with the reset button on the back of the device.
After doing this the router was stuck in the restore mode (blinking Power LED) and i tried another reset method with WPS-button.
Doesn't work.
Stays in restore mode.
Downloaded rescue utility on MAC and set up LAN IPs like described.
I get connection to the router and 192.168.1.1 restore GUI (CFE mini Web) and uploaded the last official firmware via restore tool. Upload finishes, few seconds no LEDs after upload, still blinking Power LED after upload.

Tried another attempt to upload the firmware via restore web GUI directly, same problem.
Upload does work, but then it stays in Power LED flashing mode.
What miracle is still possible to bring it back to life?

Edit:
Tried LAN port 3 instead of LAN port 5. Doesn't change anything.
Tried subnet 255.255.0.0 instead of 255.255.255.0, no change.
Tried another IP of client 192.168.1.12 and 192.168.1.102, no change.
Tried older firmware 386.41535, doesn't work.
Tried another browser, doesn't work.
Tried newest Merlin firmware upload, firmware gets uploaded but then after reboot it flashed Power LED again.

Thanks,

pappl

Edit: Solved after long search for cause, reset button stuck in pressed position. Desoldered reset button and eorks again.

 

[L&LD]

Unplug all WAN/LAN and USB devices from the router. Unplug the power plug from both the router and the AC wall plug. Be sure you left the 'power' button on the router, on. Wait a couple of minutes.

Plug the AC wall plug into AC power. Plug the power plug into the router. Test again.

Do not use Ports 5-8 (ever), use an inexpensive switch if you need more ports instead. Only use ports 1-4 on this router. For testing, you don't need to plug anything into the router, you can attempt to connect wirelessly. Use ports 1, 2, 3, or 4, only, when testing in Rescue mode and using a computer.

Double check you downloaded the correct firmware for your model. Be sure you do a hash comparison after unzipping the file and before you try flashing the router with it.

If you're in Rescue Mode, leave the router for up to an hour (or more) for it to flash the firmware and reboot on its own. Even if it says disconnected, do not touch the router until it completes.

[Wireless] ASUS router Hard Factory Reset | Official Support | ASUS Global

Fully Reset / Best Practice Setup / More

 

[PAPPL]

Unplug all WAN/LAN and USB devices from the router. Unplug the power plug from both the router and the AC wall plug. Be sure you left the 'power' button on the router, on. Wait a couple of minutes.

Plug the AC wall plug into AC power. Plug the power plug into the router. Test again.

Do not use Ports 5-8 (ever), use an inexpensive switch if you need more ports instead. Only use ports 1-4 on this router. For testing, you don't need to plug anything into the router, you can attempt to connect wirelessly. Use ports 1, 2, 3, or 4, only, when testing in Rescue mode and using a computer.

Double check you downloaded the correct firmware for your model. Be sure you do a hash comparison after unzipping the file and before you try flashing the router with it.

If you're in Rescue Mode, leave the router for up to an hour (or more) for it to flash the firmware and reboot on its own. Even if it says disconnected, do not touch the router until it completes.

[Wireless] ASUS router Hard Factory Reset | Official Support | ASUS Global

Fully Reset / Best Practice Setup / More

Did this step by step and it worked. (until reboot) :-(

- Unplugged ALL (!) and waited for several minutes, replugged wall adapter and power cable -> Power LED blinking.
- Replugged LAN on Port1, and opened ASUS firmware restoration tool (from Mac Apple Store).
- Selected official older RT-AC88U_3.0.0.4_384_45708-g6c4a2e4.trx firmware and loaded it up with the tool.
- The firmware was uploaded and another message as usual appeared. -> All LED lights on the router went on incl. red light for WAN not active.
- Wireless connections visible.
- I'm happy, after hundreds of attempts this revived my router!

Thanks a lot.

 

[PAPPL]

UPDATE:
After logging into router GUI and doing WAN and WIFI setup i noticed the WAN setting is showing "no cable attached" after first GUI login, even the WAN cable was attached.
Did a reboot from router WebGUI to possibly solve this bug and now the Power LED is blinking again.


Is it possible the router is slowly dying, e.g. capacitator replacement required?

 

[PAPPL]

Just disassembled the router. Inside all caps look ok, but the whole circuit board is greasy. The thermal pads are leaking some kind of oily fluid. This happens from cheap thermal pads. Removed all fluid and trying again.
Edit: Still not working, i believe it died.

 

[Tech9]

I would replace this router even if it starts working again. Something is obviously not right with it. AC-class routers stuck on 386 firmware and won't get new firmware features anyway. May get few security updates only down the road. See what fits your budget and take advantage of holiday sales. Popular choice models around are RT-AX86U and GT-AX6000. Both much better than your aging RT-AC88U. If you need more LAN ports - get a switch.

 

[PAPPL]

Took the router to my friend and he tried to tftp an older firmware.trx (380) with Terminal on Mac. tftp is preinstalled there. Nothing.
After waiting an hour and trying it again it booted into the UI and even after a reboot it worked.
Next day dead again. Will not spend more time on it, there is something wrong with this device.
Bought a used Asus TUF-AX5400 for 100 bucks and now i have a rock solid router with better WiFi coverage, same or better speed, more features and working 5GHz Wifi.
The TUF-AX5400 is an amazing device, even for 140 bucks new.

 

[Tech9]

The TUF-AX5400 is an amazing device

Only if you can live with the way it looks.

 

[Ripshod]

Little tangent here, but the power supply could be on the way out.

 

[PAPPL]

After attaching the routers internal plug to a „UART-TTL USB Adapter CH340G converter“ we were able to view the boot messages.
The router was doing reset commands intermittently.
Desoldered the reset button and now the router works again.
Seems the reset button is stuck in pressed position even if still clicking when pressed.

So root cause solved.