Bug#59312: boot-floppies: dbootstrap aborts when using raid partitions
Additionaly, I should mention that I was also affected by Bug#58857
where I needed to remount /dev/ram to continue with installation.
It occurs to me that the behaviour of dbootstap may(?) be consistent
with dbootstrap mounting /dev/rd/c0d0p1 as read-only then attempting
to write to it. (Although I can't check right now).
I shall attempt to fdisk, mkfs, and mount from the console before
preceding with dbootstap to see if that is a suitable workaround.
(and report back with any results)