AC68U bricked during tomato firmware attempt.

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timonoj

Occasional Visitor
Hi guys,

So...this happened. I tried to follow carefully the instructions, but after the firmware upload, the router never came back. After 45 mins, I manually attempted to clear the VRAM (via WPS button pressed at boot), with disastrous results...it looked rather dead.

However recovery seemed to do something: while the webpage seemed dead, the asus recovery tool seemed to find it. Now, if I tried the current official firmware, it crashes at around 75%. Wireshark mentions the error seems to be the router runs out of storage (?).

So I downloaded an older smaller firmware, 28MB vs the 44MB of the current version. The uploader said it was successful, and to wait for the reboot. After half hour, I kind of noticed that things go online for about 5 seconds before going all offline for about a minute. So it looks like a boot loop. What should I do next?

Thanks a lot!
 

martinr

Part of the Furniture
“So I downloaded an older smaller firmware...” Is that Tomato, Merlin or stock Asus?

What progress if any have you made? I’m fairly sure Merlin’s said more than once that it’s nigh on impossible to brick an RT-AC68U, so persevere.
 

timonoj

Occasional Visitor
“So I downloaded an older smaller firmware...” Is that Tomato, Merlin or stock Asus?

What progress if any have you made? I’m fairly sure Merlin’s said more than once that it’s nigh on impossible to brick an RT-AC68U, so persevere.

Thanks, and sorry for the lack of precision, as I was typing from my phone.
I was running initially the latest Jan 2018 stock Asus FW, but after the failed Tomato attempt, that stock one failed to upload from recovery (too big). I downloaded a stock Asus FW from ~2014 I believe. So far I'm still stuck on a bootloop, and the WPS NVRAM clear procedure doesn't seem to do anything. With that I mean, the WPS button will get the power LED flashing quickly, and after release it will reboot the router, as a NVRAM clear would normally do. However after the reboot, the router is in unusable state. It seems to nearly become available for a few seconds, then reboot.

From what I recall, there seems to be a telnet way to try to do the NVRAM clear. Would it be possible to write a tiny script that pounds the router every 1-2 seconds with telnet connections that autoexpire if it doesn't reply in the alloted time, to perform the NVRAM clear command? From wireshark I can see the firmware restore utility finds the router at 192.168.0.49 when uploading the firmware, but I can't get it to respond to ping nor anything else.

At this point I'm still hopeful, as both the WPS procedure and the Reset procedure seem to attempt to boot both in NVRAM clearing mode (albeit with no effect) and recovery mode (albeit only the recovery tool finds it).
 

Blinkyz

Senior Member
You probably need to flash with an intermediate FW.Flash it with 378.55 ( for the partition size) and flash with the latest after.
 

timonoj

Occasional Visitor
Blinkyz said:
You probably need to flash with an intermediate FW.Flash it with 378.55 ( for the partition size) and flash with the latest after.
Thanks for that! Which 378.55 do you mean? Tomato, Merlin or Stock? Could you provide a link? I didn't see the firmwares having different partition sizes, which it really looks like the issue I'm currently having.
 

timonoj

Occasional Visitor
Hahah, no worries, even though the forum might have blocked it, I received it on the reply notification email, so I got it. Yeah, it's pretty much the procedure I've been doing, with the Asus Firmware Restoration tool. I'll try to use the suggested firmware, hopefully that works. After repartitioning the memory with that fw, how should I proceed (assuming I'm successful)? Do you reckon I'd be able to try again tomato?
 

Sanna1967

Senior Member
After repartitioning the memory with that fw, how should I proceed (assuming I'm successful)?
After flashing with 378.55(if successful), flash with the latest firmware 380.69 or 384.3_alpha, or 384_10007(asus),factory reset and reconfig from beginning.
Do you reckon I'd be able to try again tomato?
sorry dont know
 

RMerlin

Asuswrt-Merlin dev
Newer RT-AC68U are not supported by Tomato. Different CPU revision.
 

timonoj

Occasional Visitor
Newer RT-AC68U are not supported by Tomato. Different CPU revision.
Ugh...How can I figure out the revision number? I don't see any kind of clue on the router labeling.

As an update...I installed the suggested Merlin 378.55. The recovery tool copied the firmware successfully, but it still will get stuck at a boot loop, rebooting every minute or two. I tried clearing the NVRAM after 10mins, to no avail (meaning, it did flash rapidly, hen rebooted...but still same behavior afterwards). What would you guys recommend?

EDIT: This is the only sign of life Wireshark shows me briefly after every reboot in the bootloop:
Frame XXXX: 60 bytes on wire (480 bits) captured on interface 0
Ethernet II, Src: AsustekC_da:25:e8, Dst:Broadcast (ff:ff:ff:ff:ff:ff)
Address Resolution Protocol (Request/gratuitous ARP)
Info: Gratuitous ARP for 192.168.1.1 (Request).
 
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timonoj

Occasional Visitor
Dang...seems my last comment got pending moderation permanently. After the 378.55 upload, it rebooted...but it still gets stuck at the bootloop. Clearing the NVRAM with the WPS button seems not to do much, but at least it gets the power led flashing rapidly. What should I try next? Any suggestions?
 

RMerlin

Asuswrt-Merlin dev
Ugh...How can I figure out the revision number? I don't see any kind of clue on the router labeling.

HW revision is found on the label. HW revision C0 and newer are not supported by Tomato.
 

john9527

Part of the Furniture
That might be because you don't use the WPS button to clear the NVRAM, you use the RESET button.
The WPS button also works. Hold in while powering on until the power LED fast blinks...release the WPS button and the router reboots with NVRAM being factory reset. I use it all the time.
 

ColinTaylor

Part of the Furniture
The WPS button also works. Hold in while powering on until the power LED fast blinks...release the WPS button and the router reboots with NVRAM being factory reset. I use it all the time.
Thanks John, I didn't know that. All the official documents I've seen only refer to the RESET button.

So the behaviour of both buttons is the same then as far as resetting or recovery is concerned? Is that true for other Asus models I wonder.
 

RMerlin

Asuswrt-Merlin dev
For some reasons, they are swapped. While the firmware is running, use the reset button for a factory default reset. While booting, use the WPS button instead - the reset button is instead used to enter firmware recovery mode.

It's the case for all Broadcom-based routers (tho HND seems to behave a bit differently regarding firmware recovery mode).
 

timonoj

Occasional Visitor
So...the reset button doesn't seem to work after waiting for a couple of seconds right after a reboot. Probably it doesn't get to load the OS to the point where it's responsive to that. If pressed before powering up, it does take you to reset, but if you wait even one second afterwards, it doesn't seem to have any effect. WPS button does seem to attempt something, but seemingly without any real effect. After the WPS reboot, it still keeps on a bootloop. I'm losing my confidence on being able to recover this little monster. I tried all merlin and official available firmwares, from the oldest to the most recent ones. The most recent ones tend to fail if the upload size is bigger than 31~32MB.

EDIT: ...OMG.

I installed the Merlin 380.57, which being under 32MB, went through. I was expecting just another series of reboots, and was checking the phone while waiting for the inevitable...but nope. This time Wifi LED came up! After an automated reboot, it came back again. And this time it stayed! I managed to connect to it, and I have successfully upgraded to Merlin 380.69, this time from the router's web UI. This little monster is tough, indeed.

So...No tomato for me for the time being, right? Any open source alternative not based on Asus official stuff? I'm not interested in all the "powered by mcafee" stuff.
 
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