RT-AC66U stuck in rescue mode & i/o errors fw uploads

[Brad]

My router came up properly, I configured it, then it somehow got stuck in rescue mode (power LED blinks slowly). I have tried EVERYTHING to do with resetting and wiping nvram and loading new firmware (old, new, stock, merlin, tomato) via the Mac Restoration tool, the CFE web GUI firmware loader and tftp and even waiting hours between steps, 30-30-30, but nothing works.

I finally got a serial connection up (a first for me) and here's what I see at boot:

**** Port Open
Decompressing...done

CFE version 6.30.39.29 (r338244) based on BBP 1.0.37 for BCM947XX (32bit,SP,LE)
Build Date: 一 10月 15 10:41:41 CST 2012 (yau@wireless-pub2)
Copyright (C) 2000-2008 Broadcom Corporation.

Init Arena
Init Devs.

Boot partition size = 262144(0x40000)
Found an ST compatible serial flash with 32 64KB blocks; total size 2MB
Found a AMD NAND flash with 2048B pages or 128KB blocks; total size 128MB
bcm_robo_enable_switch: EEE is disabled
et0: Broadcom BCM47XX 10/100/1000 Mbps Ethernet Controller 6.30.39.29 (r338244)
CPU type 0x19749: 600MHz
Tot mem: 131072 KBytes

CFE mem: 0x80700000 - 0x8094EDE0 (2420192)
Data: 0x80738B70 - 0x8073BE10 (12960)
BSS: 0x8073BE10 - 0x8074CDE0 (69584)
Heap: 0x8074CDE0 - 0x8094CDE0 (2097152)
Stack: 0x8094CDE0 - 0x8094EDE0 (8192)
Text: 0x80700000 - 0x80738B70 (232304)

Device eth0: hwaddr 60-A4-4C-6A-7F-48, ipaddr 192.168.1.1, mask 255.255.255.0
gateway not set, nameserver not set
Null Rescue Flag.
boot the image...
I/O error
I/O error
Check 2 trx result: -4, -4
Hello!! Enter Rescue Mode: (Check error)

Reading :: TFTP Server.
Failed.: Timeout occured
...repeat forever...
--------------------

If I load firmware via the tftp server, I get this:

Reading :: TFTP Server.
- last blk -
Done. 26234880 bytes read
Download of 0x1905000 bytes completed
Write kernel and filesystem binary to FLASH
Programming…copysize=26234880, amtcopy=-4
Failed.: I/O error

...and with the Mac Restoration tool:

Reading :: TFTP Server.
- last blk -
Done. 26234880 bytes read
Download of 0x1905000 bytes completed
Write kernel and filesystem binary to FLASH
Programming…copysize=26234880, amtcopy=-4
Failed.: I/O error

I'd really appreciate a reference to detailed, step by step instructions on how to update/replace the CFE, if that's the problem (which it seems to be by process of elimination) via a serial connection. I don't have telnet access (unless someone can tell me how to turn it on via serial). I've got hardware revision 1.30 and can ping & tftp it.

Any help much appreciated!
-Brad

 

[Brad]

what is the fw you are presently or before
30-30-30 for hard reset dont work with asusWrt ou Rmerlin Fw

Clear Nvram :
Power off the router
Hold down WPS button and power on the router, and keep holding WPS til leds flash rapidly(10 sec approx) and relaese WPs button.Wait 5 min and reconfig

To use the rescue mode :
First you need the Restoration Tool from asus(asus site https://www.asus.com/us/Networking/RTN66U/HelpDesk_Download/) , install it
after you need to put the router in RESCUE MODE

Follow these steps its for Ac66. You need to do all the steps from the link below

https://www.asus.com/support/faq/1000814/

*How to enter in RESCUE mode:
Power off the router: Hold RESET button and power on router,keep holding RESET til led begin flashing slowy, release RESET button and you are now in rescue mode

Thanks for the response. I'm not sure what the exact initial fw was as the thing had been in a closet for a couple of years, but I'm near certain it was stock asus.

I've been through all the steps you specified here already (way too many times) and my problem isn't getting into rescue mode, its getting out. It boots directly into rescue mode and the only thing available at 192.168.1.1 is the firmware uploading utility page. The proper GUI that you can log into doesn't appear. All attempts to upload fw end in i/o errors. See the serial output from my initial post. I haven't found any record of that exact thing happening to someone else in my web research.

So, it looks like the i/o error is the thing. Any ideas on that?

Thanks again,
-Brad

what is the fw you are presently or before
30-30-30 for hard reset dont work with asusWrt ou Rmerlin Fw

Clear Nvram :
Power off the router
Hold down WPS button and power on the router, and keep holding WPS til leds flash rapidly(10 sec approx) and relaese WPs button.Wait 5 min and reconfig

To use the rescue mode :
First you need the Restoration Tool from asus(asus site https://www.asus.com/us/Networking/RTN66U/HelpDesk_Download/) , install it
after you need to put the router in RESCUE MODE

Follow these steps its for Ac66. You need to do all the steps from the link below

https://www.asus.com/support/faq/1000814/

*How to enter in RESCUE mode:
Power off the router: Hold RESET button and power on router,keep holding RESET til led begin flashing slowy, release RESET button and you are now in rescue mode

 

[Brad]

Yeah, that doesn't work. As I said, I've done everything conventional. Unless there's a specific fw version I've missed, I think the problem is more fundamental. The serial connection reports i/o errors each time I boot or load fw. It always boots directly into rescue mode no-matter what I do.

I don't have any settings that I want to preserve. Factory new would be great.

There isn't a lot of information out there about replacing cfe's. Does anyone have straightforward instructions about how to upgrade a, ac66u hardware v1.30 cfe? I'm tech savvy, particularly around networking, but I don't need a masters degree in router firmware. I just want to get it on its feet this once. This thing is junk as it is, so I'm prepared to risk bricking it.

Thanks!
-Brad

 

[DETstru]

Not sure if this was resolved already but I'll just write it for posterity:

I had a similar problem. My ASUS RT-AC66U was constantly resetting itself to factory settings. It would do this sometimes twice a day, always when I was away from home. There wasn't much pattern to it. Sometimes it would be fine for a month and sometimes it would do it daily. I read about clearing the NVRAM and tried to do the 30-30-30 reset to fix that and I got stuck in the rescue mode loop. Here's what I did to get out of it:

1. Unplug everything from the router
2. Change the PC to a static IP (IP address to 192.168.1.10, Subnet Mask to 255.255.255.0, see this link for some help with that and the recovery tool: https://www.asus.com/support/faq/1000814)
3. Perform a 30-30-30 reset on the router. Plug the power cord in and turn on the router. Wait until the lights are stable (the power light will blink 4 seconds on/off if you're in rescue mode). Hold the reset button (you'll need a pen or paperclip) for 30 seconds, while continuing to hold the button unplug the power cord and wait 30 seconds, while continuing to hold the button plug the power in and wait 30 more seconds. Release the button. The power light should be blinking 4 seconds on/off.
4. Did the 30-30-30 reset again just to be sure.
5. Connect the PC via ethernet
6. Ping the router via the command prompt to verify TTL = 100 (open cmd, type: ping 192.168.1.1 -t)
7. Download the latest ASUS driver and rescue tool (see the link above)
8. Run the tool, upload the firmware
9. The router will reset itself and the power light should be solid
10. Wait a few minutes and path to 192.168.1.1 in your browser and you should see the GUI
11. Don't forget to switch your PC back to automatic IP

That worked for me, hopefully it'll help someone else!