The installboot regress tests use -p on octeon which works fine. I don't have serial console access to octen machines at the moment, but this should just fly as installboot already has -p support on octeon.
It's also easy to test with snapshot media as one can easily apply this patch in the installer's (S)hell prompt to /install.md with, e.g. ed(1). visa kindly tested a fresh installation with this which works fine. This leaves only loongson behind doing manual newfs rather than use -p, but I don't have access to any hardware and regress doesn't cover it. Feedback? OK? Index: octeon/ramdisk/install.md =================================================================== RCS file: /cvs/src/distrib/octeon/ramdisk/install.md,v retrieving revision 1.23 diff -u -p -r1.23 install.md --- octeon/ramdisk/install.md 6 Feb 2022 15:52:23 -0000 1.23 +++ octeon/ramdisk/install.md 11 Sep 2022 15:14:01 -0000 @@ -62,8 +62,7 @@ md_prep_fdisk() { echo -n "Creating a FAT partition and an OpenBSD partition for rest of $_disk..." fdisk -iy -b "65536@64:C" ${_disk} >/dev/null echo "done." - disklabel $_disk 2>/dev/null | grep -q "^ i:" || disklabel -w -d $_disk - newfs -t msdos ${_disk}i + installboot -p $_disk return ;; [eE]*) # Manually configure the MBR.