Thanks. What are some other options here?
I edited the winpeshl.ini in the boot.wim file, it now looks like this:
[LaunchApp]
AppPath = %SystemRoot%\system32\SetAsset.cmd
AppPath = %SystemRoot%\system32\SmartPE.exe
AppPath = %SystemRoot%\system32\SdShell.exe
My SetAsset.cmd file asks the user for input, and then executes the HP Bios Utility which I also moved to C:\Windows\System32 on the boot.wim file.
SetAsset.cmd
SET /P TAG=[Please enter the Asset Tag: ]
pushd "%~dp0"
BiosConfigUtility64.exe /setvalue:"Asset Tracking Number","%TAG%"
This actually works for my input, and does set the AssetTag in the BIOS! Which is great, But the system reboots instead of launching SmartPE.exe. Looks like I'm getting close, I'm going to try launching SmartPE and SdShell from my CMD file.
Cheers!