On Mon, 24 Aug 2020 at 21:22, Huge huge@huge.org.uk wrote:
FWIW I gave up with dual booting years ago and now just run other O/S's in a VM. I use VirtualBox, but other Hypervisors are available.
I know, I didn't really want to scrub Windows this time a-round (been Windows-less at home since 2004).
In the end, the main culprit seems to be Intel Optane [*1], their SSD / NVME RAID thing (maybe I should have chosen a Ryzen laptop :-D ). No wonder I was getting weird corruption on the EFI system partition, as Windows was reporting on chkdsk and UEFI / BIOS was reporting strange filenames in the ubuntu directory. My guess is that it's not really possible to directly write to that partition (Linux or Windows) if it's being RAIDed by Optane. Even that hypothesis doesn't make much sense to my little grey cells.
Linux boots up now. Only trouble is that I have to press F12 at boot time to get access to the boot menu otherwise Windows loads as default. I suspect this is more a grub / efi conundrum and might be fixable by setting Grub as the main bootloader. Investigation for another day.
[*1] - https://discourse.ubuntu.com/t/ubuntu-installation-on-computers-with-intel-r...
Thanks, Srdjan