Posted: Sun Jan 18, 2026 2:41 Post subject: MR7350 Bricked good
I was attempting to revert the MR7350 back to stock and was greeted with this lovely message:
Code:
root@DD-WRT_Bedroom:/tmp# fw_printenv -n boot_part
2
root@DD-WRT_Bedroom:/tmp# mtd -e linux -f write FW_MR7350_1.1.7.209317_prod.img linux
Unlocking linux ...
[flash] : Could not unlock MTD device: linux
linux: No such file or directory
Erasing linux ...
[flash] :
Skipping bad block at 0x006e0000
Writing from FW_MR7350_1.1.7.209317_prod.img to linux ... [e]
Skipping bad block at 0x006e0000[w]
Now, that looked really bad, so I did some searching on the google machine and came across this:
It looked like it was fine, and per the instructions saying it's okay to flash both I doubled down and flashed Linux2
Code:
root@DD-WRT_Bedroom:/tmp# mtd -e linux -f write FW_MR7350_1.1.7.209317_prod.img linux2
Unlocking linux ...
[flash] : Could not unlock MTD device: linux
linux: No such file or directory
Erasing linux ...
[flash] :
Skipping bad block at 0x006e0000
Unlocking linux2 ...
[flash] : Could not unlock MTD device: linux2
linux2: No such file or directory
Writing from FW_MR7350_1.1.7.209317_prod.img to linux2 ... [w]
root@DD-WRT_Bedroom:/tmp# fw_setenv boot_part 2
root@DD-WRT_Bedroom:/tmp# reboot now
Well, as you can expect, after blowing past all of the guardrails and rebooting out of a running system, I am greeted with a system that does not appear to do anything on boot and does not hand out IP addresses. I tried the 3x reboot and all the other options, but upon applying that critical thinking that I previously lacked I realize that I probably don't have much to work with here.
At this point I'm prepared to crack it open and share what I find to help build recovery docs. I don't mind soldering, and I have another primary device I can use for ISP read. I have a third backup device I can thrown on the network temporarily while I do surgery. If you have a recommendation for a level shifting serial cable, let me know.
Joined: 08 May 2018 Posts: 16758 Location: Texas, USA
Posted: Sun Jan 18, 2026 3:04 Post subject:
What was the output of:
Code:
cat /proc/mtd
Pretty sure you didn't bother looking at that. I have a feeling that partition names changed and that you may have needed to write to linux2 instead, but no idea. Those instructions were written during the early stages of device support. You should still be able to connect serial and wired ethernet and recover the device, no soldering required as the header should already be there, if I am not mistaken. Still not sure why you would even look under Broadcom for information, different animal, save and except for dual firmware partition flash layout. To recover via serial, you will need to do a 'printenv' and make note of the TFTP server IP address and expected filename output so you can configure your client PC to use that IP address on ethernet and set up tftpd32/64 or equivalent to serve the properly named firmware file. _________________ "Life is but a fleeting moment, a vapor that vanishes quickly; All is vanity"
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Linux User #377467 counter.li.org / linuxcounter.net
I have a feeling that partition names changed and that you may have needed to write to linux2 instead, but no idea. Those instructions were written during the early stages of device support.
That makes a lot of sense. If you would like a hand with documentation, I would be glad to help. Not a dig at the site, but there is a lot of old information and some things could be expanded upon.
Quote:
You should still be able to connect serial and wired ethernet and recover the device, no soldering required as the header should already be there, if I am not mistaken. Still not sure why you would even look under Broadcom for information, different animal, save and except for dual firmware partition flash layout. To recover via serial, you will need to do a 'printenv' and make note of the TFTP server IP address and expected filename output so you can configure your client PC to use that IP address on ethernet and set up tftpd32/64 or equivalent to serve the properly named firmware file.
That sounds a lot more reassuring. I was looking for anything that matched that message and figured any any port in a storm would do. I assume I'll need a level shifting serial cable. Does this one look promising?
I haven't done any jtag or SPI programming since 2019, and we used a high end programmer with break out boards the SPI equipment was lost, so we just had to improvise.
While I'm in there, I noticed you were lacking one to run tests on. If you want me to get any info, let me know.
Joined: 08 May 2018 Posts: 16758 Location: Texas, USA
Posted: Sun Jan 18, 2026 4:05 Post subject:
That one should work, as long as you keep it set for 3.3V. Just be SURE you do NOT connect the Vcc lead, whatsoever. All you should need is RX, TX, and GND. You will, however need a proper pitch connector for the router, similar to the one in this link:
I haven't done any jtag or SPI programming since 2019, and we used a high end programmer with break out boards the SPI equipment was lost, so we just had to improvise.
It's really easy to do as long as you pay attention to the details. The method is exactly the same for most all modern linksys routers so if you cannot find instructions for your specific router, search for another, ie 7350, 4300, etc. Be careful and compensate the details for YOUR router (ie filenames). It's way easier than it seems on the surface. _________________ - Linksys EA8500: I-Gateway, WAP/VAP 5ghz only. Features: VLANs, Samba, WG, Entware - r60xxx
- Linksys EA8500: 802.11s Secondary w/VLAN Trunk over 5ghz - r60xxx
- Linksys MX4300: 802.11s Primary w/VLAN Trunk over 5ghz. 2.4ghz WAP/VAP only - r60xxx
- Linksys MX4300: (WAP/VAP (7)) Multiple VLANs over single trunk port. Entware/Samba r60xxx
- Linksys MR7350: WDS Station for extended Ethernet r60xxx
- Linksys MR7500, MX8500: None in production. Just testing. r60xxx
- OSes: Fedora 40, 10 RPis (2,3,4,5), 23 ESP8266s: Straight from Amiga to Linux in '95, never having owned a Windows PC.
- Forum member #248
That one should work, as long as you keep it set for 3.3V. Just be SURE you do NOT connect the Vcc lead, whatsoever. All you should need is RX, TX, and GND. You will, however need a proper pitch connector for the router, similar to the one in this link:
Thanks for the advice. I would rather use something like that even though mine looks like it is several individual leads instead of a particular pitch. Assuming the connectors aren't way off from the gauge of the pins, I might be fine. Maybe I'll treat myself to some hook test leads.
Also, yes, I might have been tempted to add vcc on my end, but only because I would have tried to power it from the dongle instead of booting the entire unit.
