Same error here. I'm running a CHR 6.41.4 on Windows Hyper-V 2008R2, when trying to upgrade to latest version 6.42.2 and reboot I get:
Loading system with initrd
ERROR: could not find disk!
Please attach it somewhere else.
Tryed upgrade to 6.42 and 6.43rc17 with same error.
I downloaded new chr-6.42.2.vhdx (convert to vhd) and runsit on a new virtual machine, same error.
I tried same vhd on a VirtualBox machine and it works, seems to be loading others storage drivers:
VirtualBox on 6.42
i]# IRQ USERS
4 14 ide0
5 15 ide1[/i]
HyperV 2008R2 and VirtualBox on 6.41
# IRQ USERS
4 14 ata_piix
5 15 ata_piix
Any workaround? CHR dropped support to 2008R2 on purpose?