So I've been trying to slipstream updates on my Windows Server 2016 Datacenter edition (1607), as I often deploy test servers and wanted to have an ISO with the updates baked-in to accelerate the process.
Pretty much every guide I can get my hands on tells me to do the same thing, so here are the commands I am using.
Mount-DiskImage C:\slipstream_updates\iso\base_server_2016_datacenter\SW_DVD9_Win_Svr_STD_Core_and_DataCtr_Core_2016_64Bit_English_-2_MLF_X21-22843.ISO
robocopy /s /e E:\ C:\slipstream_updates\copied_base_iso_files
Dismount-DiskImage C:\slipstream_updates\iso\base_server_2016_datacenter\SW_DVD9_Win_Svr_STD_Core_and_DataCtr_Core_2016_64Bit_English_-2_MLF_X21-22843.ISO
Set-ItemProperty C:\slipstream_updates\copied_base_iso_files\sources\install.wim -Name IsReadOnly -Value $false
dism.exe /mount-wim /wimfile:"C:\slipstream_updates\copied_base_iso_files\sources\install.wim" /mountdir:"C:\slipstream_updates\wim_mountpoint" /index:1
dism.exe /image:"C:\slipstream_updates\wim_mountpoint" /Add-Package /PackagePath:"C:\slipstream_updates\cumulative_update_files\august\ssu"
dism /image:"C:\slipstream_updates\wim_mountpoint" /cleanup-image /StartComponentCleanup /ResetBase
dism /unmount-image /mountdir:"C:\slipstream_updates\wim_mountpoint" /commit
cd "C:\slipstream_updates\copied_base_iso_files\"; & 'C:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Deployment Tools\amd64\Oscdimg\oscdimg.exe'-bootdata:"2#p0,e,bboot\Etfsboot.com#pEF,e,befi\Microsoft\boot\Efisys.bin" -u1 -udfver102 C:\slipstream_updates\copied_base_iso_files C:\slipstream_updates\iso\WindowsServer2016_SSU_KB4132216.iso
In the previous example, I tried to slipstream KB4132214 which is the SSU required to install further Cumulative Updates from the Microsoft Catalog according to the information page. After this, I would do the same procedure, using the newly created ISO to try and add KB4343887 (August Cumulative Updates) and create a separate ISO file.
But then after installing a new machine with the newly created ISO, the updates simply don't show up. Not in the Installed Updates panel (none of the updates show up, not even KB4132216 that was installed at first), not by running Get-Hotfix, and running "winver" tells me it is still "Version 1607 (OS Build 14393.0)".
While creating the ISO files, every command finished successfully, and looking at the created ISO files, I see the size of that file increase between steps, so I'm assuming files are indeed getting copied in there.
I have tried using the same process to slipstream a different Cumulative update, KB4103720 which is usually the first that the server tried to fetch from Windows Update upon launching "Check for Updates" on a newly installed server straight from the base ISO, but to no avail.
Am I missing something? Am I possibly doing something wrong here?