On Sun, 7 Oct 2018, Andreas Gustafsson wrote:
the new device (hd1) ends up numbered as ld4 and the system disk (hd0) as ld5:
Looks like this is intentional: https://github.com/qemu/qemu/blob/master/hw/arm/virt.c#L806
You'll need to change the -append argument to pass root=ld5a instead.