I think there should be a prompt in the installer before overwriting the partition tables. The current behavior is, when selecting the whole disk, to overwrite the partition table directly.
I am suggesting this because I once by mistake double pressed enter at the «Partitioning Disks» stage, selecting my main drive but also selecting the default partitioning option. I quickly canceled the operation, but it had already deleted my GPT table. I was able to recover it, but it should have asked, like it does on the «(E)dit» option. I would suggest modifying install.md like this (example from the amd64 version): --- install.md 2021-06-28 15:07:22.277778218 +0200 +++ install.md.ask 2021-06-28 15:08:44.776914131 +0200 @@ -71,7 +71,7 @@ case $resp in [wW]*) echo -n "Setting OpenBSD MBR partition to whole $_disk..." - fdisk -iy $_disk >/dev/null + fdisk -i $_disk echo "done." return ;; [gG]*) @@ -81,7 +81,7 @@ fi echo -n "Setting OpenBSD GPT partition to whole $_disk..." - fdisk -iy -g -b 960 $_disk >/dev/null + fdisk -i -g -b 960 $_disk echo "done." return ;; [eE]*)