Posted: Sun Apr 08, 2012 9:19 Post subject: Debricking WRT54G... Help!!!
OS: Windows XP SP3 (fresh install, no a/v, no firewall)
Problem: I am trying to recover my router WRT54G v4 which I bricked when I accidentally uploaded a 2.6 kernel firmware. I have soldered a header on JP2 and borrowed a JTAG cable from a friend who previously used it to recover his WRT54G v2. However, I can't seem to get it to work with my v4. Here's the error message I get when I send a probe:
Code:
Probing bus ... Done
Instruction Length set to 5
CPU Chip ID: 11111111111111111111111111111111 (FFFFFFFF)
*** Unknown or NO CPU Chip ID Detected ***
*** Possible Causes:
1) WRT54G/GS is not Connected.
2) WRT54G/GS is not Powered On.
3) Improper JTAG Cable.
4) Unrecognized CPU Chip ID.
Odd Symptoms:
Whats really odd is that in the beginning only the router's power LED was flashing uncontrollably. It has been this way since it was bricked.
Now when I connect the JTAG cable, only an amber or orange light glows along with a white light. However, when I disconnect the JTAG cable and power up the router, power LED starts flashing as usual.
Troubleshooting:
1. HairyDairyMaid installs and starts successfully.
2. Checked LPT port is working fine with no conflicts and uses any interrupt assigned.
3. Checked soldering connections and everything seems alright.
The problem is I still can't connect to the router via LPT. I've read the wiki and searched the forums but I don't know how to handle this situation. Can someone kindly offer some advice?
Read the jtag article in the wiki, and check your soldering with a multimeter.
Serial recovery might be a better choice than jtag. _________________ SIG:
I'm trying to teach you to fish, not give you a fish. If you just want a fish, wait for a fisherman who hands them out. I'm more of a fishing instructor.
LOM: "If you show that you have not bothered to read the forum announcements or to follow the advices in them then the level of help available for you will drop substantially, also known as Murrkf's law.."
Joined: 26 Jan 2008 Posts: 13049 Location: Behind The Reset Button
Posted: Sun Apr 08, 2012 15:02 Post subject:
make sure you do not have you cable connected backwards. That used to be a common problem.
Meaning: you do not have pin 1 of the jtag cable connected to pin 12 of the routers pcb (header plugged in backwards)
also.. power up the router, count to 1, launch the jtag utility.
EDIT: I can't find a pic of a v4's pcb. Make sure you are using the 12 pin jtag connector and not the 10 pin serial (x2) connector on the pcb _________________ [Moderator Deleted]
jp1 is jtag.. earlier you stated you connected to jp2.. that is serial.
That was it! Thank you so much for that!!
I backed up CFE, NVRAM, and KERNEL, each three times. Is there any other precaution I need to take before I start the recovery process?
While doing my research, I came across posts on DD-WRT which said that since an incompatible firmware flash brick my router, I would only need to erase NVRAM and perhaps the Kernel.
Is that really the case? So I can skip erase:wholeflash and CFE flash? Just erase NVRAM and KERNAL and then tftp stock firmware?
In case if I do have to flash the CFE:
1. Which CFE file should I use? My own that I backed up earlier? or download one from your website? There are two different CFE files for v4 routers posted on your website, cfe_WRT54Gv4.zip(106KB) and WRT54G_v4.0_CFE.zip (102KB). Which one should I use?
2. Would I have to change my MAC address after flashing a CFE from your website?
