Posted: Fri May 06, 2011 9:02 Post subject: E2000 Bricked, Blinking Power LED, TFTP works but.. no boot?
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 :/
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.
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?
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
Last edited by fggs on Fri May 06, 2011 9:32; edited 1 time in total
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!
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
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!
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
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)?