Thanks for the pointers guys, I'll document the path I followed, since I suspect
many will come down this route and it's easy to forget how it all started.
1: Problem. I have an ASUS RT-N66U. It produces very annoying syslog (e.g. emergency NTP date updated)
and hangs from time to time.
I could just replace it but the hardware is fine and the world does need more landfill
2: Action , looked into OpenWRT. They say they have little/no support and you should try DD-WRT
So I download all these. Unsure of the difference between "big" and "mega" (curiously mega is MUCH smaller) I opt for
"big" . I follow the instructions on "https://wiki.dd-wrt.com/wiki/index.php/Asus_RT-N66U". It installs fine.
However I get many odd errors, I post a question and ..... "YOU GOT THAT TOTALLY WRONG!!!" (politely)
..............stop ... think .....
So, what did I do wrong:
A: I guess the biggest mistake was going to "router-database". I now see there are many scattered warnings to not do so.
Things I didn't know, and you may well also not know:
There are many ways to install firmware on many different routers. The ASUS
RT-N66U looks like one of the easier ones, in that it's possible to just use the
original OEM "Upgrade Firmware" link on the router. This has a (useful)
gotcha. The OEM "upgrade Firmware" checks for the version/model. This means you
need to upload an RT-N66U specific firmware. If you look in:
https://download1.dd-wrt.com/dd-wrtv2/downloads/betas/2020/ and around there you
will search in vain. I assume this is because it's and old router and folks are
after a more interesting life have moved to newer, sexier kit. All is not lost however
once you've replaced the OEM firmware with the DD-WRT flavour, it has a "upgrade
Firmware" button which does not check for a model/version. This means you can
then load a "more generic" firmware, probably newer. This is hard to understand at
first as you need to understand the lingo used on this site:
OEM Firmware: Is called "Stock Firmware" or "stock build" or "Factory FLASH" (However as you can see above The term Factory FLASH is also used for a "trailed build" which installs using the OEM "upgrade Firmware" button
Hardware Specific builds: Are called "Trailed builds" (no idea where this name comes from)
More generic builds: Don't seem to have a specific name but are often called non-trailed builds
So it becomes a two stage process:
1: Install a "reasonable" but probably OLD "Trailed build" for the RT-N66U (using the OEM "Upgrade Firmware" button)
2: Use the "Upgrade Firmware" button on the DD-WRT firmware to install a more generic build (but newer and better?)
The question then just remains, which to builds to use for the above two step process?
Well for step one, I've already used: dd-wrt.v24-40559_NEWD-2_K3.x_big.bin (see
above) It works but with pretty major bugs hopefully I'll find the "upgrade
firmware" button feature works OK (otherwise , I'll be back).
The question is then what to use for step2?
In this case I have some help. The above two members offer suggestions:
3rd one leaves me a little flummoxed (is that the old MPS processor , that lacked a test&set?) Given the pointers
in the N66U specific page above I guess I should steer clear of the K26 and use the K3X, but let's investigate:
Well "broadcom" seems to contain lots of specialised firmware. I'm guessing things like "if you want a VPN" etc
The "broadcom_K3X_mipsel32r1" has only one item of firmware. I'm guessing made for a particular purpose.
The "broadcom_K26" has lots of more generic looking items, but I'm avoiding as suggested
So "broadcom_K3X" ...wow lots of stuff.....including: dd-wrt.v24-41874_NEWD-2_K3.x-big-RT-N66U.trx
Which I take to be a "big" build for the "RT-N66U" in ".trx" format (meaning I
can just load it via the "upgrade firmware" button. This sounds like a "one step
solution". I didn't even need the initial install. However let's looks around:
There is also a "dd-wrt.v24-41874_NEWD-2_K3.x_mega_RT-N66U.trx" (a mega build, again very small???)
There are 11 ".trx" images (loadable via "upgrade firmware") all have what look like ASUS router names in their filename
There are 28 ".bin" images (loadable via a different mechanism, documented elsewhere)
Picking one of these "dd-wrt.v24-41874_NEWD-2_K3.x_mega-e900.bin" I'm guessing this is for the Linksys E900
[ http://en.techinfodepot.shoutwiki.com/wiki/Linksys_E900 ] as this is also using a Broadcom chip [ BCM5357C0 ]
So that, by extension, covers most of the '.bin' except:
Method 1: Flashing with Web GUI ...
3: Upload the Firmware ...
3. This section is written for the DD-WRT GUI. An OEM firmware interface will be different. ...
3. Click the "Browse" button and select the DD-WRT .bin file you downloaded and confirmed.
So it looks like the DD-WRT Web GUI also needs a .bin file ? What is difference between the two:
So it looks like a signature in bytes 8-11 and also at the tail (01aaff0c
onward) has some descriptive text "RT-N66U" et al.
So my guess is that these are in fact the same binary, just one is "marked up"
to allow the OEM Firmware to accept it, the other is not. So I'd hope the DD-WRT
firmware would accept both, maybe just not checking the signature? Alternatively
the DD-WRT firmware may simply required a '.bin' file.
I think both possibilities suggest I should try the .trx file.
It's always a safe bet with ASUS routers to use the .trx file.
This device is working like a charm, I'm already owning three N66U
I'm installing the *big-RT-N66U.trx files from Broadcom_K3x folder. Don't get confused, nowadays our old devices are using a 4.x Kernel, the folder wasn't renamed
The N66U is very forgiving.
If I manage to somehow destroy the installed firmware, there is still the emergency mini CFE or TFTP server available.
In this case I go for the smaller *mega* files since my devices sometimes refuse the bigger files in emergency mode / TFTP.
After this I upgrade to a working *big*.trx via the DD-WRT webgui again.
Windows TFTP Syntax:
I followed the install instruction esp. WRT using the WPS button to reset the RAM before flashing.
I'm not sure what it reset (I did see the all LED flash telltale) but oddly the device stayed on 10.177.... which was where it was before. Unfortunately I'd unplugged all the other cables and just had a laptop with Debian on it to attach to it . If I'd simply left all my cabling in place, it would have been fine. This is because I run it as a wireless AP. It had no DHCP etc (this would have come for my central DHCP sever) ...hard to locate it's IP. [ this is all before starting the re flashing ]
Anyhow, in short, not sure what is supposed to be "reset" by a "WPS button to Clear NVRAM" does not seem to be much.
I did choose the "reset to factory defaults after flash" option and it came up on 192.168.1.1 after flashing.
Ultimately, it mostly worked, aside from one obvious problem. Before I had a 2.4Ghz and a 5Gz radio. There were two slots in the GUI to configure them etc. Now I only have a 5Ghz on as
Wireless Physical Interface wl0 [5 GHz]
BTW I opted for DD-WRT v3.0-r41874 big (01/03/20)
The 2.4Ghz really is missing, it's not just the GUI, I can't detect the signal.
I guess this is a subject for that thread, not here so I guess I'll go over there and see what folks have to say.
But did not recognise the term, I was reassured as the significant mentions on that page are:
The NVRAM issue has been resolved in newer CFE versions (and K3X builds). ...
IMPORTANT: DO NOT USE K2.6 builds if using CFE v188.8.131.52 (64K nvram) or NEWER!!!
This was resolved with DD-WRT K3X builds (kernel 3.x) which extended nvram to 64k, and can be used for any CFE version.
So since I didn't know what CFE was and seemed if I used a K3X build I didn't need to worry. Does the RT-N66U page need an update?
I'll take some time over this (i.e. RTFM) and , if it's possible I'll update my initial "long" post , to explain there is another step. It's always hard to follow a "script" that says so A , B, then C ...several pages of doc, then oh BTW you must do X before doing A .
I won't attempt to update the Asus_RT-N66U as I don't feel I have sufficient knowledge
1. (re) install latest firmware from Asus "standard ASUS WRT firmware"
1.1 Use standard ASUS Firmware to re-flash with "Merlin WRT firmware"
2.1. Backup CFE
2.2. Use the Merlin firmware to Update CFE to 184.108.40.206
4. Use the Merlin Firmware + CFE-220.127.116.11 to (re) update to DD-WRT 43516
So I'm installing the CFE once and reinstalling the firmware 3 times!!?
This feels wrong. If the CFE is produced by ASUS. I'd assume they have a route
to install it? (also a place on their site to download it from) the CFE binary
I'd be installing here comes from a site in Russia.
So the worst case would be, go back to ASUS firmware then update CFE using ASUS
tools, them reinstall DDWRT?
Q1: Is the CFE produced by ASUS
Q2: Do they provide a download (issue of provenience)
Q3: Do they have a process to update it?
ABTW, is the term CFE one used by ASUS? Do they call it something else?
Best case [least work] would just be use my existing DDWRT and "dd" over the raw
character device (I can see the script for Merlin uses "mtd-write")