#!/usr/bin/env bash
# flash.sh — flash stock OpenBSD install ISO to USB
# Usage: ./flash.sh /dev/sdX
set -euo pipefail
DEV="${1:-}"
[[ -n "$DEV" && -b "$DEV" ]] || { echo "Usage: $0 /dev/sdX"; exit 1; }
case "$DEV" in /dev/nvme*|/dev/sda|/dev/mmcblk*|/dev/vd*) echo "ERR: refusing internal $DEV" >&2; exit 2;; esac
URL="https://cdn.openbsd.org/pub/OpenBSD/7.6/amd64/install76.iso"
ISO=/tmp/install76.iso
[[ -f "$ISO" ]] || { echo "[*] downloading $URL"; curl -fL -o "$ISO" "$URL"; }
echo "About to flash $ISO -> $DEV. Type yes:"
read -r ANS; [[ "$ANS" == "yes" ]] || exit 1
sudo dd if="$ISO" of="$DEV" bs=4M status=progress conv=fsync oflag=direct
sudo sync
sudo eject "$DEV"
echo "EJECTED — pull, plug into edge box, install"