Hi, @hayaoki7
From this post I see that you want to use a different hardware part of MC56F81000 family (the MC56F81666VLF). I don`t know if you managed to insert the SDK correctly in the toolbox, but I will explain to you step by step how this can be done.
1. In the MCUXpresso SDK builder after you choose the hardware part from Proccessor -> dsc tab and then select the hardware part you want to build the SDK, you also have to select all the additional packages that are supported for the version 2.7.3, including FreeMASTER, because we use those middlewares in our toolbox.


2. After you download the SDK, you have to extract the content from the zip file into a new directory "{toolbox_path}\NXP_MBDToolbox_DSC\DSC_Platform_SDK\SDK_2_7_3_MC56F81666"
3. When you open a model, for example the mc56f81000_flexpwm_edge_aligned.mdl, you have to change some settings from the Hardware Settings tab. In the Hardware Implementation -> Target hardware resources -> Hardware you have to choose your Hardware Part, which is going to be MC56F81666VLF.

4. After you have done that, a pop-up will show up to warn you have to tell a path to the SDK folder that you have just download and extract in the step 2.

5. Then you will click Apply and save the model.
6. In order to build the application successfully, you also have to do some changes in the mex Configuration Tools file attached to the model. For that, please open outside MATLAB the mc56f81000_flexpwm_edge_aligned.mex and go to File -> Switch processor

7. From here, you also have to look up and choose for your hardware part, as shown below. And then clcik Finish.

8. From this point, if any errors appear in the current configuration, you have to resolve them by yourself in order for a successful build. Then you will save the configuration file and try to build the model.
It should work with no errors. Let me know if this approach worked.
Thank you! Regards!
Stefan.