Posted: Mon Jul 04, 2016 8:23 Post subject: Serial flash help - bricked ea6900
Finally managed to brick EA6900. Ping is fine on TTL=100 but tftp failing with timeout error. Tried every trick posted here and decided to go with serial flash route. Opened the router and first relief is header pins are there so no need for soldering. Now problem is no labels on them so which pins are what?
Also I can't seems to find guide on commands for serial flash. Can any kind soul pls post either link or detail step by step for novice like me . I've got both stock Linksys and initial ddwrt fw and not sure which is recommended.
I connected the cables (layout looking from front of router) and no response. Later I swapped gnd and tx, powered on router and managed to see booting process. But CTL-C, ESC, SPACE, all these failed to halt booting.
Check your serial adapter and the wire connections. The adapter should be of the 3.3V variety. Also, in my experience, not all adapters are created equal. I had this experience with a modified CA-42 cable and was never able to stop the boot process. Upon switching to a CP2102 Breakout adapter, everything worked as desired.
I'd CP2102 which worked with other modem but decided to order PL2303HX variant from ebay. Only cost £2.33 and arrived in 2 days (UK mainland). There's a driver issue on Windows 8.1 and need 1.2.10. Once setup and putty output, followed DDWRT serial recovery wiki with linksys tftp application.
-ctheader was an invalid switch. Typed "help flash" (without quotes) to confirm and other options which was -noheader.
Anyway it was good and big relief to see command output "LINKSYS" and login page . One more thing, I also had to manually put gateway (192.168.1.1) to initially access setup page.
Joined: 30 Sep 2018 Posts: 47 Location: United Kingdom
Posted: Sun Dec 16, 2018 12:20 Post subject:
Hi, I think I'm in the same situation now as you was, so I have an question. What firmware did you flashed into bricked ea6900? And how did you installed xvertex on it? Thanks _________________ Bible in short: Don't be religious. Just love God and follow Jesus
Joined: 30 Sep 2018 Posts: 47 Location: United Kingdom
Posted: Tue Dec 18, 2018 14:36 Post subject:
I have just question what should be flashed under what names/partitions.
Partitions of EA6900 are named different than it is in DD-WRT serial-recovery guide.
Thanks.
Joined: 30 Sep 2018 Posts: 47 Location: United Kingdom
Posted: Tue Dec 18, 2018 21:08 Post subject:
From CFE it looks different.
I can't tell you exactly names but they are named like files where first part is nflash0 or nflash1 and after dot there are trx, os, os2
Dd-wrt guide states that flash1.trx should be used as destination in CFE but there is no such of thing.
I will look to ea6700 forums - thanks for advice
PS.
I did search EA6700 forum and found two important information:
1. I should flash nflash1.trx
2. I shouldn't do 30/30/30 as I probably deleted nvram and Can't get it work on stock firmware anymore.
To be honest I think it may be the issue - that someone before did 30/30/30 to this router as it was bricked but as I saw on serial console - linksys firmware did boot but after boot was almost complete every time it crashed.
It is hardware issue or result of cleared NVRAM.
However, I think I flashed exactly that partition (nflash1.trx) with dd-wrt and now it say there is checksum error or something - basically - image is bad.
I just wondering if it may be result of wrong serial interface - Because that what I have - I'm not sure is exactly 3v3 - it may be 5v.
But It works - I have console, no glitches, commands works.
And after all transfer is going trough LAN cable not trough serial.
But maybe it anyway can be wrong.
Joined: 30 Sep 2018 Posts: 47 Location: United Kingdom
Posted: Wed Dec 19, 2018 15:15 Post subject:
OK. I did tested few more firmwares (including asuswrt), and always the same. Router crashes when boot is almost complete.
In AsusWRT there is moment in the boot when you can hit enter (Serial Console) and have access not to CFE but to proper AsusWRT partition.
So I have that access and can play with settings, but don't know what to do.
If I will exit from console, boot process resumes and after few seconds - crash.
Im not sure, but I think that always few lines before it crashes - I noticed that before it crashes (I'm sure it was in asus-wrt and in both linksys firmwares) something related to eth2 crashes, and in general - it's in area after eth2 setting up, and also there is always also wl0 wl1.
I checked CFE utilities, but all tests that found there router passed. Now I would like to localise the problem. Only option is to disable functionalities somehow, or doing boot in steps, but how to do this?
As I said, I can access linux console on first moments of the boot, so if someone knows how to step boot up in asus-wrt it would be lovely - I would be able to determine what is the problem, and than I could avoid it, or localise broken hardware.
Joined: 30 Sep 2018 Posts: 47 Location: United Kingdom
Posted: Thu Dec 20, 2018 0:12 Post subject:
Thanks for answer. Yes I'm trying serial recovery. I already tried a lot, but I think it must be hardware. Today I reflowed PCB again in vapour phase oven, but no success nor any change so if it's hardware it's definitely not cold solder.
If I won't repair it tomorrow I will keep it just for spares, as antennas may be useful as radiators as well.
Update:
Today I was cleaning up after this horrible fight and realised myself that power brick supplied by seller is not genuine for this router.
It was 12V 0.2A instead of 12V 3.5A - this is massive difference.
Just after, I took another brick to test, and guess what? Router is OK. It starts, everything works. I don't know how I missed that was just wrong brick. I just assumed that seller gave me whole set as should.
Now I can carry on with upgrading firmware
Posted: Mon Mar 23, 2020 3:43 Post subject: EA6900 Serial Recovery
Hey guys, I need some help.
I wanted to install dd-wrt on my Linksys EA6900. The router was working fine, before I started I decided to perform a factory reset by holding the reset button for 10s, later the router rebooted after reset, then I wasn't able to access the router configuration page. It gives me no ip, the ethernet lights are continuously On(no flashing), power lights is On doesn't flash on boot. I tried to connect my serial Adapter to the white connector,I get no response on putty.
Please help me, my whole internet connection is down.