KB5005112 may be required! Or your ISO built via W10UI may not boot KB5010427 needs KB5005112 (says MS) 2021-08 Servicing Stack Update for Windows 10 Version 1809 for x64-based Systems (KB5005112) Last Modified: 8/9/2021 Size: 13.8 - Security Update Moreover, installing each update individually onto a virgin Win10x64-LTSC (1809) OS = msg "Update not applicable." ==> KB5005112 was the fix <==
https://forums.mydigitallife.net/threads/windows-10-hotfix-repository.57050/page-678#post-1723064 Boots/installs fine without the old ssu you mentioned.
It's an almost 3-year-old update, I would imagine it got superseded by something else(maybe the LCU). I'm most likely wrong, tho.
Thx @Enthousiast Well this should only result in an, none working recovery Maybe it is being superseded by LCU @shhnedo
All new updates: https://forums.mydigitallife.net/threads/windows-10-hotfix-repository.57050/page-678#post-1725921
Updated the 1809 Updates Overview: https://forums.mydigitallife.net/th...-17763-xxx-pc-rs5.77945/page-216#post-1490183
Updated the 1809 (17763.2746.1.6) Updates Overview: https://forums.mydigitallife.net/th...-17763-xxx-pc-rs5.77945/page-216#post-1490183
Updated the 1809 (17763.2803.1.3) Updates Overview: https://forums.mydigitallife.net/th...-17763-xxx-pc-rs5.77945/page-216#post-1490183
Updated the 1809 (17763.2867.1.7) Updates Overview: https://forums.mydigitallife.net/th...-17763-xxx-pc-rs5.77945/page-216#post-1490183
Updated the 1809 (17763.2928.1.6) Updates Overview: https://forums.mydigitallife.net/th...-17763-xxx-pc-rs5.77945/page-216#post-1490183