Here's a guide from DD-WRT on TFTP recovery flashing. Use a known good firmware file ( preferably the one you were using before this latest flash that bricked the router ) . Give it a read through.. if I can be of help or answer specifics I'm happy to do so.
In the end, I couldn't recover from its bricked state. I was able to TFTP the Tomato firmware and it said it flashed successfully but it still does not boot up.
What exactly is the routers current behavior? When turned on, do the LEDs exhibit abnormal on/off/blink states? When a computer is connected via ethernet cable to the router, does the router respond to pings at 192.168.1.1 consistently? What error is being returned when you attempt to access the GUI webpage.. timeout, connection refused etc.
Thanks Sean for trying to help out.
Does sound like you've covered all the bases. As far as NVRAM reset, I *believe* the reset button on the E4200 should do that. However, this following procedure may be worth a shot as I'm not sure if it's a per device or per firmware ( tomato ) implementation but does specifically erase the NVRAM on my RT-AC68P: With the router off, press and hold the WPS button ( the blue button the back ) and turn the router on while continuing to hold. On my 68P after about 15 - 20 seconds the power LED will begin to flash rapidly indicating NVRAM has been cleared. If you get the same response, that would be a great sign and upon releasing the button it should reboot. If not, hold for a total of 30 seconds just in case and then release. Observe for indications the router is rebooting.. if it is, let it reboot and cross your fingers. If not, shut it off.. offer it a cookie or perhaps a shot of top shelf whiskey.. then turn it back on and see what it does
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Sean B, if I wanted to try to revive this router using the serial port on the E4200, and do this as cheaply as possible, I was perhaps thinking of purchasing any needed parts from Ebay through the cheapest China or other Asian seller that I can find. It would take over a month for stuff to ship to me from there but I am in no hurry. What parts would I need such as a USB to Serial cable, standard pin header, etc.? I'm not sure of the terminology to search for on Ebay. Also, does there have to be any soldering involved or can a pin header (if I can find it on Ebay) just be placed into place there temporarily? Thanks for any help that you may be able to offer.
This was purely for a fun project. I already purchased a used Asus RT-N66u for a replacement. If it was very cheap and easy to fix, then I would try it. If not, then I would just throw it away. I don't own a soldering iron and would not buy one just for this. I've read they make solderless/push in/press in pin headers but ebay doesn't really have much or extremely cheap. This may be too involved for me.
Yes, I have tried as per post 4029 but nothing worked. Do you know now what exactly happened that caused this brick situation in this particular model of router and why the TFTP flashing of the firmware does not work?
I'd rather not speculate as to the cause.I actually live in Canada so I don't believe shipping is really cost effective. Thanks for the offer, anyways.@Dent If you're in the United States and you feel like spending a little bit of money, you can mail me the E4200 and I can attempt to recover it for you (I'm happy to pay return shipping), including possibly leaving a permanent pin connection for serial + including a free USB TTL adapter if asked. The TFTP method is "tricky" a lot of the time, and I've found several TFTP clients that don't behave correctly (both on Windows as well as Linux).
I would not trust push-in solderless pins. They aren't going to make a good connection.
There's no real way to determine "what" "bricked" the unit (I use quotes around brick because I simply can't tell if it truly is or isn't). It's not like there's magical permanent-storage logs that hold such information.
If this attempt is based out of fun/curiosity ( implying the end result and possible damage caused by the attempt is not a big deal ) and soldering is a concern then feel free to improvise. Use bare wire ends and fashion a way to get them to maintain contact with the copper rings of each through-hole. Possibly sticking a section of stripped wire through the hole, folding each side down to a moderately taunt state and then use a common arts-an-crafts hot glue gun and put a small dab top an bottom.. then cut any excess wire left sticking around on the bottom so they don't manage to short to anything else. Or perhaps get some mini-hook test clips ( pictured below ) at a local electronics store or on ebay.. can get a 5-pack for a couple bucks. Flatten the hook end so it's L shaped and cut the foot of the L to a width that just barely fits through the hole. Worst case ( barring missed stray wire strands causing a short ) would be there isn't enough contact and you won't get a terminal connection, or just barely enough contact resulting in randomly lost connections and/or jibberish appearing in your terminal programs console.
