MathWorks does not recommend modifying the support package as there may be updates to it during future release. However, you could create a custom support package.
The following documentation pages may be of assistance to you in developing support for your target hardware:
1) The following guide from the File Exchange is a great resource for developing custom device driver blocks for your hardware:
https://www.mathworks.com/matlabcentral/fileexchange/39354-device-drivers
2) To develop device driver blocks using System Objects, which provide the most functionality, you may also reference this guide in the documentation:
https://www.mathworks.com/help/supportpkg/armcortexa/device-driver-blocks.html
3) If your hardware is using an ARM processor, we also provide tools for developing new targets. These guides walk you through developing a custom target for the different ARM processors that are supported.
ARM Cortex-A:
https://www.mathworks.com/help/supportpkg/armcortexa/target-sdk.html
ARM Cortex-M:
https://www.mathworks.com/help/supportpkg/armcortexm/target-sdk.html
ARM Cortex-R:
https://www.mathworks.com/help/supportpkg/armcortexr/develop-a-target.html
Please note that the available Hardware Support Packages can be found at this link:
https://www.mathworks.com/hardware-support/home.html
You may also request a new Hardware Support Package here:
https://www.mathworks.com/hardware-support/request-hardware-support.html
Finally, MathWorks Consulting Services may be available for assistance in creating a Hardware Support Package. If this is of interest to you, they can be contacted at:
https://www.mathworks.com/services/consulting/proven-solutions/developing-embedded-targets.html
