Linksys EA6700, NO 2.4GHz wifi

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setum
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PostPosted: Sat Jul 10, 2021 2:35    Post subject: Linksys EA6700, NO 2.4GHz wifi Reply with quote
I have a Linksys EA6700 that I flashed with dd-wrt. I used this tutorial to in install dd-wrt: https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=320463. Everything works fine except 2.4 GHz wifi.

In dd-wrt, I noticed following:
1. I can see the radio in the web-ui and configure ssid
2. after restart the 2.4GHz is available for few seconds and then the ssid disappears.
3. in the little time that ssid is visible, if I am quick and try to connect to 2.4GHz, it gets past authentication, but the wifi disappears while obtaining IP address.

After reading several other dd-wrt topics related to '2.4GHz not working', I have tried following:
1. removed any connected USB device
2. factory reset router from web-ui
2. tried various 2.4GHz bands (including 1, 6 & 11) in place of default
3. tried both 20/40 mhz
4. tried old firmware (r23204), and new firmware (r47000) and things in between (r36410, r46446, r46885) -- all exhibit same problem.

in the stock firmware, 2.4GHz wifi works fine, it is only in dd-wrt where it fails.

what more should I try?
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kernel-panic69
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PostPosted: Sat Jul 10, 2021 2:47    Post subject: Reply with quote
If you didn't follow the installation guide to the letter, then you will likely run into problems.
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setum
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PostPosted: Sat Jul 10, 2021 2:58    Post subject: Reply with quote
kernel-panic69 wrote:
If you didn't follow the installation guide to the letter, then you will likely run into problems.


Ok. The only place I didn't follow the guide to the letter was in step #3 & #4 -- instead of using tftp to downgrade the stock firmware, I flashed the lower version firmware directly through stock-ui and then verified in the ui that the firmware was indeed downgraded, then continued with step #5 onwards.

I will redo the installation, this time to the letter and report the results back.
kernel-panic69
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PostPosted: Sat Jul 10, 2021 3:21    Post subject: Reply with quote
Not the steps I was even referring to. I'm afraid to ask if you reset the router in any part of this process...
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setum
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PostPosted: Sat Jul 10, 2021 4:25    Post subject: Reply with quote
kernel-panic69 wrote:
I'm afraid to ask if you reset the router in any part of this process...


not as a part of process, but several times outside of it.

> factory reset from dd-wrt ui or erase nvram -- several times in attempts to make 2.4GHz work
> after having tried everything and failed to get 2.4GHz wifi working. I tried my luck with OpenWrt. In OpenWrt, no WiFi was working, radio itself was not showing up in the UI, this router is not fully supported by OpenWrt, but it was worth a try.
After OpenWrt, I tried to revert back to dd-wrt, but something went wrong and I assumed I have bricked my router. Then I interrupted the router startup by pulling power and repeating it 3 times. This reset the router and brought it back, on dd-wrt now, still no 2.4GHz.
> I never used the reset button to reset.
kernel-panic69
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PostPosted: Sat Jul 10, 2021 4:46    Post subject: Reply with quote
And you wonder why 2.4 band doesn't work.
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setum
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PostPosted: Sat Jul 10, 2021 5:00    Post subject: Reply with quote
kernel-panic69 wrote:
And you wonder why 2.4 band doesn't work.


not clear why.

2.4GHz was not working to begin with, right after the initial dd-wrt installation, following the installation guide 'to the letter', expect for the downgrading stock-firmware part (step #3 & #4)

All the various things that I tried came after that... which certainly didn't made anything better, it may have worsened something, although not noticeable to me...

Anyways, is there anything I can try now to fix 2.4GHz wifi?
tedm
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PostPosted: Sat Jul 10, 2021 18:38    Post subject: Reply with quote
This is a fairly advanced router to be flashing to dd-wrt it's almost probably a good thing there's no wiki guide for it since it has lots of things to trip up newbies:

It's one of those ones with the "linksys 32k nvram bug" There are various hacks out there in that link to the discussion you posted that supposedly dynamically resize the nvram but mostly they don't work. What DOES work is flashing a modified CFE but anyone new to dd-wrt has almost an 80% chance of bricking their router if they do that.

It came out during that time period that the FCC was looking at requiring router makers to restrict 5Ghz radios so they would not cause interference with some other band - the FCC ultimately did do that. Earlier router specimens had older unlocked firmware newer ones had locked firmware. Since the router auto-updates, most used ones have locked firmware and have to be backreved - since the newer firmware will not allow downgrading you have to tftp - and that means catching the router at exactly the right time during it's boot. Which is almost impossible.

My guess is your radio is not coming up due to a config problem. Meaning you think you have 64k of nvram available but actually only have 32k, and you are trying to stuff in more than 32k worth of variables. As a result during startup the router is loading garbage from the nvram and shutting off the radio

To fix this my recommendation is as follows:

1) Backrev to the antique hong kong firmware from Linksys (it's mentioned in that thread you posted)

2) verify that the 2.4ghz radio is indeed working properly

3) Follow the steps for flashing Fresh Tomato:

https://www.linksysinfo.org/index.php?threads/guide-flash-linksys-ea6300v1-ea6400-ea6500v2-ea6700-ea6900v1-0-1-1-with-tomato.73877/

including the steps to replace the CFE with a corrected version that properly defines 64k nvram and deletes that "backup" partition (which is what creates the 32k nvram bug to begin with)

4) Assuming FT is working fine then you can upgrade to dd-wrt and turn on all the go-fast acceleration hardware.

Expect to spend most of the day screwing with this. Brickage factor is also high. But fortunately these are cheap as dirt on the used market.

For a while I had one of these in my "to be effed with" bin. But I decided that with the cheap-as-dirt cost of a used Netgear R7000, it's go-fast hardware, and the ease of putting dd-wrt on it, that it would save me a lot of time to just drop stock firmware on the Linksys and sell it off then use the money to "trade in" for a more dd-wrt friendly router.
kernel-panic69
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PostPosted: Sat Jul 10, 2021 18:48    Post subject: Reply with quote
The likely problem is the user reset the router. At no point in any thread does it say to reset an EA-series Broadcom Linksys on DD-WRT for obvious reasons. You also do not do a 30-30-30 or nvram erase for obvious reasons. The startup script does work to some degree, however, using the XWRT-Vortex CFE is the ultimate fix and a process that is not for the light at heart. One wrong move and the router is bricked and you have to use serial to do anything, if you are lucky.
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setum
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PostPosted: Sun Jul 11, 2021 8:45    Post subject: Reply with quote
tedm wrote:
My guess is your radio is not coming up due to a config problem. Meaning you think you have 64k of nvram available but actually only have 32k, and you are trying to stuff in more than 32k worth of variables. As a result during startup the router is loading garbage from the nvram and shutting off the radio


the nvram usage generally hovers between 24k to 30k. Although once it went above 32k+ and I had to re-flash dd-wrt.

I'll flash Fresh Tomato including replacing CFE. As you pointed I should expect to spent most of day doing this, I'm planning to do this next weekend.

Thanks for all the help. I'll report back on how it went.
kernel-panic69
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PostPosted: Sun Jul 11, 2021 10:54    Post subject: Reply with quote
Just be very careful with modifying the CFE to ensure the mac addresses are correct. Easiest way to install DD-WRT after you've converted the CFE is via the mini webserver.

https://forum.dd-wrt.com/phpBB2/viewtopic.php?p=1123961

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setum
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PostPosted: Mon Jul 12, 2021 4:05    Post subject: Reply with quote
tedm wrote:
I decided that with the cheap-as-dirt cost of a used Netgear R7000, it's go-fast hardware, and the ease of putting dd-wrt on it, that it would save me a lot of time to just drop stock firmware


Does USB 3.0 port works with dd-wrt in Netgear R7000?
It didn't in case of Linksys EA6700, but I am not sure now, if this was also due to 32k nvram issue.
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