How do I install drivers using Burn and DPInst after MSI installation?

Question

I have a setup MSI for our application, and I also have signed FTDI drivers that need to be installed as well. I'd like for them to be installed with Burn rather than the WiX MSI to keep CustomActions out of the MSI (however, I've tried the CA route as well).

I've tried putting the instruction in an ExePackage, but the SourceFile attribute asks for the file location during build, not runtime (e.g. <ExePackage Id="InstallDrivers" DisplayName="Installing Drivers" SourceFile="[InstallFolder]Drivers\DPInst.exe" InstallCommand="/SA /SW" PerMachine="yes" After="MyMSISetup" Description="Installing the FTDI drivers needed for device communication." /> doesn't build).

Is there a way to tell Burn to execute DPInst using the file location of where the drivers will be after installation of the MSI? Currently the MSI copies the driver files and DPInst into a Drivers folder in the install directory. After looking online and here on Stack Overflow, I doesn't seem like anyone else is doing this.

I've also tried using the CustomAction route in the MSI, but the CustomAction fails to execute. I'd like the drivers to be installed with Burn, but if they work with the MSI I'd settle for that. Currently the MSI copies the files to the Drivers folder, and the CustomAction looks like this:

<InstallExecuteSequence>
    <Custom Action="Install_Signed_Driver" After="InstallFiles">NOT INSTALLED</Custom>
</InstallExecuteSequence>

<Fragment>
    <CustomAction Id=Install_Signed_Driver" Execute="deferred" Directory="Drivers" ExeCommand=&quot;[Drivers]DPInst.exe&quot; /SW /SA" Return="ignore" />
</Fragment>

As near as I can tell, the custom action never runs. I've even taken off the /SW and /SA switches to see if anything loads, and nothing.

Answer 1

Per StackOverflow's suggestion, I'm posting what I found here. I was never able to get Burn to run DPInst for the driver installation, but was able to get the CustomAction to work using Can't seem to get Wix to install driver.