PeaSoup

For me, I had to... 1. create the SCCM boot ISO first 2. extract the BOOT.WIM 3. mount BOOT.WIM with imageX 4. modify the winpeshl.ini and commit to BOOT.WIM 5. Inject the modifed BOOT.WIM back into the boot ISO using a program like PowerISO Yes, it is a pain to do especially if you make frequent changes or have multiple boot ISOs for different environments, but once you have a finalized boot ISO, you'll only need to do this once.

I've been running into the same issue, and here's what worked for me. After some research and testing, it looks like the root cause is due a delay for the iLo mounted ISO to show up as a drive letter in WinPE. In my smsts.log, it showed the SCCM build app check for BOOT.WIM only on D drive (physical), but the mounted ISO was actually on E drive. By the time the ISO was properly mounted on E, the SCCM build app had already stopped. I modified the \windows\system32\winpeshl.ini file in BOOT.WIM to add a 10 second delay before it attempts to launch the SCCM build app, so the file now looks like this: [LaunchApps] %SYSTEMDRIVE%\sleep.exe, "10" %SYSTEMDRIVE%\sms\bin\i386\TsBootShell.exe sleep.exe is not normally on the build disc, it was something I added myself. Instead of sleep, you also simulate a delay with ping -n, or create a batch file that loops through checks for the existence of BOOT.WIM before TsBootShell is launched. Hope this helps! Edit - winpeshl.ini is picky when used with parameters, see this post here for more info.