We have a custom target (based on grt.tlc or ert.tlc) that we have been using in older versions of MATLAB for a long time. We always place the .tlc file under
where <matlabroot> is usually located at C:\Program Files\MATLAB\RXXXXx\ on Windows OS.
Now, we upgraded to a more recent version that has the Simulink toolstrip (R2019b and newer). The code generation and build works without issue, but we are having trouble with using External Mode, since every time I try to use the "Run on Custom Hardware" app, the system target file switches back to one of the default targets (grt.tlc or ert.tlc). Why is this?