Interesting! Windows Server 2019 working on ESX 4.1!
As expected, the installation process is almost identical to Windows Server 2012 and 2016. The key is to use BIOS version SLIC 2.5.
Except I’ve encountered a tricky problem that the valid license key won’t activate, it returns with “windows server 2019 error -xc004f069″.
It turns out the the source ISO is an evaluation copy, so all you have to do is to convert the Eval copy to Retail version by:
DISM /Online /Set-Edition:ServerStandard /ProductKey:xxxxx-xxxxx-xxxxx-xxxxx-xxxxx /AcceptEula
To determine upgrade path and other available edition:
DISM /online /Get-TargetEditions
For the evaluation/retail version of Windows Server 2016 Standard, you can also convert to the retail version of Windows Server 2016 Data Center using the same command and the appropriate product key.
DISM /Online /Set-Edition:ServerDatacenter /ProductKey:xxxxx-xxxxx-xxxxx-xxxxx-xxxxx /AcceptEula
Update: Apr 11, 2021
It turns out VM will lost its customized CPUID parameter after Veeam backup restoration, BIOS SLIC 2.5 parameter holds though.
So you have to add it back again, or the VM will keep crashing every now and then.
However, if the VM is deployed via template, then there is no problem at all.