OpenWrt support for Linksys MX4200

Sure, you're welcome I'm more than happy to help wherever i can. :roll_eyes:

Please read this thread: Qualcommax & ath11k board calibration & BDF data woes - #52 by andyboeh

Hey, lets stay positive, as an opensource project openwrt is a team effort.
Me and the rest of the users are thankful to all contributors.
Pointing fingers is not beneficial to anyone, there is enough hatred on the internet.

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There are quite a few iwinfo outputs here showing higher values than that. Why did you think that the hardware was capped at 17 dBm?

Regarding the workarounds to get phy2 working with a higher Tx-Power, I am genuinely surprised that anybody would go to such great lengths to solve a problem that you can literally solve replacing a file and rebooting.

  • Download this BDF: https://filebin.net/g69bex9e0joyeno8
  • Copy it to /lib/firmware/ath11k/IPQ8074/hw2.0/board-2.bin with scp
  • rm /lib/firmware/ath11k/IPQ8074/hw2.0/cal-ahb-c000000.wifi.bin possibly?
  • reboot
  • (optional) Enjoy a cup of coffee with the time you saved

It's not as if you're getting better results doing it any other way from what I can see.

phy0-ap0  ESSID: "xxx"
          Access Point: 80:69:1A:xx:xx:xx
          Mode: Master  Channel: 36 (5.180 GHz)  HT Mode: HE80
          Center Channel 1: 42 2: unknown
          Tx-Power: 19 dBm  Link Quality: unknown/70
          Signal: unknown  Noise: -107 dBm
          Bit Rate: unknown
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11ac/ax/n
          Hardware: embedded [Qualcomm Atheros IPQ8074]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy0

phy1-ap0  ESSID: "xxx"
          Access Point: 80:69:1A:xx:xx:xx
          Mode: Master  Channel: 4 (2.427 GHz)  HT Mode: HE20
          Center Channel 1: 4 2: unknown
          Tx-Power: 20 dBm  Link Quality: 66/70
          Signal: -44 dBm  Noise: -107 dBm
          Bit Rate: 84.8 MBit/s
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11ax/b/g/n
          Hardware: embedded [Qualcomm Atheros IPQ8074]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy1

phy2-ap0  ESSID: "xxx"
          Access Point: 80:69:1A:xx:xx:xx
          Mode: Master  Channel: 112 (5.560 GHz)  HT Mode: HE80
          Center Channel 1: 106 2: unknown
          Tx-Power: 27 dBm  Link Quality: 52/70
          Signal: -58 dBm  Noise: -108 dBm
          Bit Rate: 327.4 MBit/s
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11ac/ax/n
          Hardware: embedded [Qualcomm Atheros IPQ8074]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy2

We all thought power for PHY2 was limited hardware-wise at first and @lytr pointed me to the fact :

(BTW are you aware that the limitations we have now succeeded in overcoming, for PHY2 - a 17dBm limit - only applied to users in ETSI countries?)

I don't like downloading random files from the internet and 'planting them' (if you will) in my devices.

Besides the possible security risks - you can call me paranoid, perhaps I am - which I can now avoid, the only thing I now need is my OpenWRT Snapshot.

Plus, I genuinely enjoy tinkering with computers/devices and (if I can) like to help them become viable long term using OpenWRT.

If I was in it for the Coffee-break I wouldn't use OpenWrt and just stick with whatever junk the OEM ships it with :wink:

Fair enough. As I understand it, hard limits in the BDF file are not hardware limits. Or a comment two weeks ago is at first for me either. The iwinfo outputs I'm talking about are months old.

I simply can't comment about the limitations you've overcome, apart from saying congratulations. I just never had any issue with the 3 radios being present, or their power, since I firstly installed OpenWrt. And that's before there were any snapshots and we were building the firmware from SpectreDev's repo. But I've always avoided the BDF that's currently on openwrt/firmware_qca-wireless because of the radio issue.

I totally get your point about files on the internet but I guess you do realise that the snapshots are pulling the BDFs from openwrt/firmware_qca-wireless and those are coming from PRs of the likes of lytr and SpectreDev. I guess that the fact that it's merged by OpenWrt's maintainers gives you some peace of mind. For me, it's pretty much the same.

It's all good in the end. The more people tinkering and investigating the better. I'm glad you're sharing your findings.

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Hi, I'm new here and I just came across this post, I have had a MX4200 for couple years now and have always wanted to install something that gives me more control over the radios and the router. @lytr do you know if the 17dBm limit is the limit of the radio transmitter or just the max power legally allowed in ETSI countries? Is there any other region based power limitations in the firmware?

Hi, I recently flashed my MX4200v1 (EU version) with @lytr's latest builds. However, the router seems to crash several times a day, sometimes isolating devices in the same subnet until a manual reboot, which is annoying because it makes Home Assistant dysfunctional. Is this a known issue, and is there any way to fix it?

I'm not using them, but if I were to troubleshoot the crash, I would set up the system's log file to a non-temporary location e.g. /root/system.log and increase the size e.g. 10MB. You can do that under System->Logging in LuCI or editing /etc/config/system. Then review the log after a crash and see what's going on.
OpenWrt's main branch is their development branch. lytr's builds are based on that with a few changes that are on PRs to be merged if accepted. It's totally speculative but it's possible that the crashes are to do with OpenWrt not being stable on main or, quite likely too, devices or settings specific to your network. But you'll have to establish what's causing the crash in the first place.

The 17dBm limit for the ETSI region is set in the BDF file. There are no such restrictions for the US country. I don't know if similar limits are set for other countries/regions.

Any estimate on how far away a stable release is for this device?

So if we set region to US, would we get the stock limit that's probably very low or would we jut not have any limitations?

I'm using SNAPSHOT r0-b017d6c, I was able to get the Radio 2 to work using 00 country code and at 28dBm too!

You will have the limit that applies to the US. It's best to just check it.