Apalis iMX8 QM and EMC/Wireless certification

Apalis imx8 QM 1.1B

we are using the apalis imx8 qm 1.1b with the Toradex supplied Unictron AA222 MHF4 in our device. for our emc/wireless certification. the lab is asking about changing the radio power of the board and transmitting frequency. i was wondering what is the best way to achieve this in torizon 5.1. Would it be also possible to get additional documentation to help with the certification process.

Hi @nkj,

Does this link help?

Can I ask why you are using Torizon 5.1 instead of 5.3?


Our system is currently in development. For the testing phase we used 5.1 version and for time being have stayed with it. but plan would be to upgrade 5.3 in time.

regarding the link. those documents are helpful. but dont say how i can change the wireless power would this work through a command like iwconfig ?

This post has details on commands that will change the power for you.

i have changed to torizon 5.3 build 7
using the command shown in the link i am able to change the wifi power down but to get to it transmit at its max setting of 20dBm allowed doesn’t seem to have an effect.

steps i am doing

  1. Bring down wireless interface using nmcli. nmcli conn down <connection_name>
  2. Set device max txpower to 20dBm. sudo iw dev mlan0 set txpower fixed 2000
  3. Bring up the the wireless interface using nmcli. nmcli conn up <connection_name>
  4. Check connection strength using iw dev mlan0 info this still shows txpower as 15 dBm

I have also set the regulatory domain to CH the country i am in using iw reg set CH

i have tired the same set of commands on a x86 computer running ubuntu 20.04 and there the power correctly goes up and down. could this be bug in torizon ?

Any idea why the TXPower might be not going upto 20dBm

I am able to set it using those commands but it seems the max is 1200. Are you sure that 2000 is a valid value?


Hi Drew,

thank you for checking.
if you run the command iw list you should see the information about the wifi card and maximum allowed TXPower. In the frequencies section you will see its upto 20 dBm which corresponds to 2000mBm

* 2412 MHz [1] (20.0 dBm)
* 2417 MHz [2] (20.0 dBm)
* 2422 MHz [3] (20.0 dBm)
* 2427 MHz [4] (20.0 dBm)
* 2432 MHz [5] (20.0 dBm)
* 2437 MHz [6] (20.0 dBm)
* 2442 MHz [7] (20.0 dBm)
* 2447 MHz [8] (20.0 dBm)
* 2452 MHz [9] (20.0 dBm)
* 2457 MHz [10] (20.0 dBm)
* 2462 MHz [11] (20.0 dBm)
* 2467 MHz [12] (20.0 dBm)
* 2472 MHz [13] (20.0 dBm)
* 2484 MHz [14] (disabled)

* 5040 MHz [8] (disabled)
* 5060 MHz [12] (disabled)
* 5080 MHz [16] (disabled)
* 5170 MHz [34] (23.0 dBm)
* 5190 MHz [38] (23.0 dBm)
* 5210 MHz [42] (23.0 dBm)
* 5230 MHz [46] (23.0 dBm)
* 5180 MHz [36] (23.0 dBm)
* 5200 MHz [40] (23.0 dBm)
* 5220 MHz [44] (23.0 dBm)
* 5240 MHz [48] (23.0 dBm)
* 5260 MHz [52] (20.0 dBm) (no IR, radar detection)
* 5280 MHz [56] (20.0 dBm) (no IR, radar detection)
* 5300 MHz [60] (20.0 dBm) (no IR, radar detection)
* 5320 MHz [64] (20.0 dBm) (no IR, radar detection)
* 5500 MHz [100] (26.0 dBm) (no IR, radar detection)
* 5520 MHz [104] (26.0 dBm) (no IR, radar detection)
* 5540 MHz [108] (26.0 dBm) (no IR, radar detection)
* 5560 MHz [112] (26.0 dBm) (no IR, radar detection)
* 5580 MHz [116] (26.0 dBm) (no IR, radar detection)
* 5600 MHz [120] (26.0 dBm) (no IR, radar detection)
* 5620 MHz [124] (26.0 dBm) (no IR, radar detection)
* 5640 MHz [128] (26.0 dBm) (no IR, radar detection)
* 5660 MHz [132] (26.0 dBm) (no IR, radar detection)
* 5680 MHz [136] (26.0 dBm) (no IR, radar detection)
* 5700 MHz [140] (26.0 dBm) (no IR, radar detection)
* 5745 MHz [149] (13.0 dBm)
* 5765 MHz [153] (13.0 dBm)
* 5785 MHz [157] (13.0 dBm)
* 5805 MHz [161] (13.0 dBm)
* 5825 MHz [165] (13.0 dBm)

Yes, but I’m curious if you can change the value at all.


changing to a lower value like 5dBM does work as than it reduces to that. additionally i have tested the same commands on a x86 computer and there it works going to higher power as well. I need to be able to change the power level for wireless certification of the device.

Hi @nkj

We are working on an alternative driver from NXP which also has manufacturing mode support from Azurewave. I think that driver is needed to do the full certification. I am able to set the power to 20dBM with that driver does work. Interestingly, when I dump the frequencies, they are all listed with 20dBM as the max.

Unfortunately we don’t yet have this ready for customer usage but hopefully soon. I’ll be sure to post here when we have something available.


Hi Drew,

Thank you for the update. Would you have an approximate timeline on when this new driver would be available in Torizon so we could plan our testing accordingly.

Additionally I was wondering the Apalis iMX8 module has been out for a while and if other customers have ran into the same issue. As this is our first time trying to certify the wireless device. I was wondering if the power control is required when using pre certified components or is our EMC Lab being especially pedantic.


Hi Nitish,

I don’t have a specific timeline but I hope it will be in the next month or so. It’s unclear at the moment if it will be integrated directly in our Torizon builds or if it will be a documentation page showing you how to do it yourself in a custom build.

I know there are other users working with certification and I am not surprised that power control is required. I do know that some of the users used the proprietary driver for certification but they did a fully custom build to enable that driver.


Would be good if it is integrated in torizon somehow without requiring a custom build. as i really like the concept of torizon which with torizon builder kinda takes the hassle out having to build a custom image manually.

Sure, that’s understood. We are definitely discussing it but given other priorities it will likely not be integrated into the formal releases for some time.