E2000 Bricked, Blinking Power LED, TFTP works but.. no boot?

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Junkmauler
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Joined: 02 Apr 2008
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PostPosted: Fri May 06, 2011 9:02    Post subject: E2000 Bricked, Blinking Power LED, TFTP works but.. no boot? Reply with quote
I have an E2000 which I had dd-wrt on, I went to upgrade my dd-wrt from (dd-wrt.v24-16214_NEWD-2_K2.6_mega-e2k-e3k.bin) to the latest version and accidentally picked a file that was not for the E2000... I upgraded to dd-wrt.v24.16773_NEWD-2_K2.6_mega.bin (note this one is missing the e2k,e3k in the filename)

Anyways long story short, WOOPS!

Now my router is blinking power LED, I can ping it for 4-5 seconds when it first boots, however even after trying to tftp using tftp.exe and the tftp2.exe here on the forums to either a correct dd-wrt or Linksys firmware, it accepts the transfer, sends the data.. but then... nothing!

Repowering the unit does not seem to work, doing a 30/30/30 does not work either... I'm to the point now I want to attempt something with a JTAG (I think).

The E2000 has the JTAG ports in the WAN CAT5 connector, however its been speculated here on the forums how to make this connector. Apparently its not as simple as just creating a serial cable, it has to have TTL or something (not sure someone help me here please).

I want to make/buy this connector and learn how to fix a bricked router via a serial connection, but I don't know enough about it. And there's soooo much information here on the forums its hard to find specifics, especially when dealing with the E2000 with JTAG port in the WAN connector :/

Can someone PLEASE help? Smile
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fggs
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Joined: 28 Jan 2008
Posts: 1741

PostPosted: Fri May 06, 2011 9:14    Post subject: Reply with quote
Actually there's no JTAG in WAN port, it's serial in WAN port. And you need a TTL-to-RS232 adapter for it to work, buy a cheap Nokia CA-42 and build the connector for WAN port.

Here's a few interesting threads for you:

http://www.dd-wrt.com/phpBB2/viewtopic.php?p=547802

http://www.dd-wrt.com/phpBB2/viewtopic.php?t=62998
Junkmauler
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Joined: 02 Apr 2008
Posts: 23

PostPosted: Fri May 06, 2011 9:20    Post subject: Reply with quote
fggs:

Ok that sounds like a plan, however...
The cable you mentioned is USB on one end and serial on the other, how does this work... don't I need serial on both ends?

At least this is all I could find on eBay...

http://cgi.ebay.com/NOKIA-connectivity-cable-driver-ca-42-OEM-NIB-/280671264438?pt=LH_DefaultDomain_0&hash=item41594f9eb6#ht_748wt_698
fggs
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Joined: 28 Jan 2008
Posts: 1741

PostPosted: Fri May 06, 2011 9:25    Post subject: Reply with quote
Yes, correct, you need serial on both ends and this cable is made like this: USB-to-Serial in one end and Serial-to-TTL in the other end, it also suits for users that don't have access to serial port anymore.

I saw the link you posted, seems the right one Wink


Last edited by fggs on Fri May 06, 2011 9:32; edited 1 time in total
Junkmauler
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Joined: 02 Apr 2008
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PostPosted: Fri May 06, 2011 9:26    Post subject: Reply with quote
Or perhaps that cable already uses serial over USB, sorry if that is the case, I'm just new to this.. I know I have the intelligence to do this but having never used a serial or JTAG port before its a little confusing at first.. I still don't know what capabilities you get from having this connection, or what software is needed.

I'm assuming it allows you to upload the firmware directly to the memory and perhaps reset the nvram.. *shrug*

All I know is I'm tired of not knowing at least how to attempt to fix a Linksys router when the connector is right there! Razz
Junkmauler
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Joined: 02 Apr 2008
Posts: 23

PostPosted: Fri May 06, 2011 9:33    Post subject: Reply with quote
Can you please give me a heads up as to what software I'll need to upload the firmware once I have my cable built, and any pointers? If I'm successful I will document all my steps and take pictures so the E2000 unit is completely documented here on the forum Smile
fggs
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Joined: 28 Jan 2008
Posts: 1741

PostPosted: Fri May 06, 2011 9:38    Post subject: Reply with quote
I've edited my last post, you were correct and I didn't explained in a proper way.

Yes, with serial you can make it accept the correct firmware and don't forget to erase nvram like you said.

Here's another good link: http://www.dd-wrt.com/wiki/index.php/Serial_Recovery
fggs
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Joined: 28 Jan 2008
Posts: 1741

PostPosted: Fri May 06, 2011 9:39    Post subject: Reply with quote
As barryware always instructed, I would upload STOCK firmware first and from there, flash dd-wrt back following the wiki for your router.
Junkmauler
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Joined: 02 Apr 2008
Posts: 23

PostPosted: Fri May 06, 2011 9:54    Post subject: Reply with quote
fggs:

Thank you for all of your help, I'll be ordering one of those Nokia cables.. I'm still stumped as to why TFTP seems to work correctly but the router just doesn't boot the firmware. (perhaps the nvram is completely pooched?)

I wish there was a simple way to clear the nvram (I guess a 30/30/30 isn't doing it)

Once I get the cable and figure the pin outs I'll document all of my steps!
fggs
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Posts: 1741

PostPosted: Fri May 06, 2011 10:02    Post subject: Reply with quote
If I recall, the CFE from these new routers (E series) has wrong command to flash via tftp, forcing the need of serial for fixing it..
Junkmauler
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Joined: 02 Apr 2008
Posts: 23

PostPosted: Fri May 06, 2011 10:16    Post subject: Reply with quote
fggs wrote:
If I recall, the CFE from these new routers (E series) has wrong command to flash via tftp, forcing the need of serial for fixing it..


Is there a way to fix the CFE once I get this puppy up and running? Or is that too low level to even access via the serial connection?

Would be great to know WHY tftp fails, and give other users an option to fix it, in case they ever need it.
fggs
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Posts: 1741

PostPosted: Fri May 06, 2011 10:27    Post subject: Reply with quote
It's a bug inside CFE's sourcecode, not fixable, at least not even Eko couldn't..
Junkmauler
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PostPosted: Fri May 06, 2011 10:32    Post subject: Reply with quote
fggs wrote:
It's a bug inside CFE's sourcecode, not fixable, at least not even Eko couldn't..


Yes I just did some light reading on the subject, and it seems CFE is like a BIOS binary, boots the device then tells the firmware to load.

If I'm not mistaken most units are now open source from Linksys are they not? (But I'm guessing this probably doesn't include the CFE.. go figure huh)... Probably only includes the firmware.. bummer man.

And Linksys probably never updates the CFE after a unit has hit the market because its not easily flashable.. total bummer!

I wonder what exactly the CFE is doing wrong, like I said it takes the tftp transfer correctly and all, just doesnt seem to do jack crap with it. lol Smile
fggs
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Posts: 1741

PostPosted: Fri May 06, 2011 10:35    Post subject: Reply with quote
CFE is Broadcom, only manufacturers has access to its sourcecode..

It's probably flashing the firmware at the wrong flash partition, and I bet this is on purpose to prevent 3rd party firmware flashing through tftp Smile
Junkmauler
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Joined: 02 Apr 2008
Posts: 23

PostPosted: Fri May 06, 2011 10:40    Post subject: Reply with quote
fggs:

You're awesome Smile

Also for reference do you happen to know if this unit has an easily accessible JTAG port in addition to the serial port (yes I know it'll be under the hood)?
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