Enable Spread Spectrum on iMX8

I would like to enable Spread Spectrum following this guide:

My understanding is that I have to patch a board_parameter(board_param_t param) function in a board.c file, but I can not find this file in yocto. I have been looking in the linux-toradex code

git clone git://git.toradex.com/linux-toradex.git --branch toradex_4.14-2.0.x-imx

but the files

$ find . -name board.c

do not seem to be the correct ones and the firmware folder is empty except for a makefile. Can someone point me to the correct files/recipes in yocto?

Dear @bdecker

This board.c is part of the SCU. You can find the SCU here:

We normally don’t modify the SCU firmware but here some documentation about how to build the final images:


Hi @benbrenson

I’m not sure what you mean. The board.c file is this:

You need to edit line 411 and 414 according to the NXP document. After that you just need to rebuild it.


Hi @benbrenson

Unfortunately it’s a bit obfuscated. This article here worked for me with the newest SCFW sources (L4.14.98_2.3.2_SCFWKIT-1.3.2). At least it compiled. You need to use the gcc recommended in the article (ggcc-none-eabi):


Hi Stefan,

thanks for your reply.

Maybe I got something completely wrong. I’m going to explain my steps a bit further:

First off all I fetched your Version of the scfw from GitHub - toradex/i.MX-System-Controller-Firmware

And then I tried to compile it:

cd imx8-toradex-scufw/src/scfw_export_mx8qm_b0

make qm R=B0 B=apalis

But then I got a lot of “No such file or directory” errors.
So I downloaded the official scfw porting kit from NXP and copied your Repository into it:

imx8-toradex-scufw/src/scfw_export_mx8qm_b0/platform/board/mx8qm_apalis → scfw_porting_kit_1_2_2/src/scfw_export_mx8qm_b0/platform/board/mx8qm_apalis

imx8-toradex-scufw/src/scfw_export_mx8qm_b0/Makefile → scfw_porting_kit_1_2_2/src/scfw_export_mx8qm_b0/Makefile

After this I tried again to compile the scfw but get the following errors:

Generating platform/board/mx8qm_apalis/dcd/imx8_ramid1_dcd_1.6GHz.h
Generating platform/board/mx8qm_apalis/dcd/imx8_ramid2_dcd_1.6GHz.h
Generating platform/board/mx8qm_apalis/dcd/imx8_ramid1_dcd_1.6GHz_retention.h
Generating platform/board/mx8qm_apalis/dcd/imx8_ramid2_dcd_1.6GHz_retention.h
Compiling platform/drivers/pmic/fsl_pmic.c
Compiling platform/drivers/pmic/pf8100/fsl_pf8100.c
Compiling platform/board/mx8qm_apalis/board.c
platform/board/mx8qm_apalis/board.c:64:10: fatal error: drivers/rgpio/fsl_rgpio.h: No such file or directory
64 | #include “drivers/rgpio/fsl_rgpio.h”
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
Makefile:461: recipe for target ‘build_mx8qm_b0/board/mx8qm_apalis/board.o’ failed
make: *** [build_mx8qm_b0/board/mx8qm_apalis/board.o] Error 1

So I make something completely wrong here.



Hi Stefan,

I’ve taken a look into i.MX-System-Controller-Firmware/src/scfw_export_mx8qm_b0/platform/board/mx8qm_apalis at master · toradex/i.MX-System-Controller-Firmware · GitHub

The repository doesn’t provide any further source files required for building the scufw.
It seems that only toradex specific files and binaries can be found there.

I’m now not sure against which version of the NXP SCFW porting kit it is compiled.
I need to modify the board.c in order to activate the spread spectrum feature.

This guide User Guide of Spread Spectrum Support for i.MX 8Qu... - NXP Community mentioned that it should be possible to activate the feature since SCFW porting kit V1.2.2.


Hi @stefan_e.tx,

thank you very much for link to the article. After following those steps everything worked for me!

But, it only worked for the newest Kit (SCFWKIT-1.3.2)!

The SCFW Kit L4.14.98_2.0.1_SCFWKIT-1.2.5 described in the article didn’t work for me.



Perfect, tanks for the feedback! I internally sent a request that we change the version found on the page.