Although it is always better to try to repair a Windows OS by booting from the original Windows ISO, it is not always present on your E2B USB drive!
This tip works for most Windows 8 or Windows 10 systems. It allows you to repair the OS without needing to have any ISO or WinPE type payload file on the E2B drive and it will always use the correct matching version of WinRE to repair or access the original OS installation - even if you don't actually know what OS version was installed.
It relies on the fact that most Windows 8/10 systems will already contain a \Recovery folder on the internal hard disk containing a winre.wim file. It could be contained within a separate Recovery partition or it could be in the main NTFS boot partition.
This method allows you to boot to the Recovery console and from there you can use the various repair/troubleshooting repair features or drop to the command shell and type in your own commands.
Since E2B\agFM\Ventoy can boot from .wim files, we can directly boot from the winre.wim file like this...