diff --git a/install.sh b/install.sh
index 941d90c..38a7fbe 100644
--- a/install.sh
+++ b/install.sh
@@ -5,15 +5,16 @@
 #
 # Configurable via env:
 #   REPO_URL   git url (default: this public repo)
-#   REF        branch/tag/commit to check out (default: main)
+#   REF        branch/tag/commit (default: remote's HEAD branch, e.g. main/master)
 #   DEST       clone destination (default: /opt/linux-bootstrap)
 #   Any extra args are forwarded to bootstrap.sh, e.g.:
 #     curl -fsSL .../install.sh | bash -s -- --skip hardening
 #
 set -Eeuo pipefail
 export DEBIAN_FRONTEND=noninteractive
+
 REPO_URL="${REPO_URL:-https://gitea.big-chungus.me/moritz/linux-bootstrap.git}"
-REF="${REF:-main}"
+REF="${REF:-}"                       # empty -> auto-detect remote default branch
 DEST="${DEST:-/opt/linux-bootstrap}"
 
 say() { printf '\e[34m[install]\e[0m %s\n' "$*"; }
@@ -40,19 +41,32 @@ if ! command -v git >/dev/null 2>&1; then
   fi
 fi
 
-# 2. clone or update
-if [[ -d "$DEST/.git" ]]; then
-  say "updating existing clone at $DEST"
-  $SUDO git -C "$DEST" fetch --depth=1 origin "$REF"
-  $SUDO git -C "$DEST" checkout -f "$REF"
-  $SUDO git -C "$DEST" reset --hard "origin/$REF" 2>/dev/null || true
-else
-  say "cloning $REPO_URL -> $DEST"
-  $SUDO git clone --depth=1 --branch "$REF" "$REPO_URL" "$DEST" 2>/dev/null \
-    || $SUDO git clone --depth=1 "$REPO_URL" "$DEST"
+# 2. resolve ref: explicit env wins; otherwise ask the remote what its default
+#    branch is (handles main vs master without guessing).
+if [[ -z "$REF" ]]; then
+  REF="$(git ls-remote --symref "$REPO_URL" HEAD 2>/dev/null \
+          | awk '/^ref:/ {sub("refs/heads/","",$2); print $2; exit}')"
+  if [[ -z "$REF" ]]; then
+    say "could not detect default branch, falling back to 'main'"
+    REF="main"
+  else
+    say "remote default branch: $REF"
+  fi
 fi
 
-# 3. run bootstrap, forwarding any extra args
+# 3. clone or update
+if [[ -d "$DEST/.git" ]]; then
+  say "updating existing clone at $DEST ($REF)"
+  $SUDO git -C "$DEST" remote set-url origin "$REPO_URL"
+  $SUDO git -C "$DEST" fetch --depth=1 origin "$REF"
+  $SUDO git -C "$DEST" checkout -B "$REF" "origin/$REF"
+  $SUDO git -C "$DEST" reset --hard "origin/$REF"
+else
+  say "cloning $REPO_URL ($REF) -> $DEST"
+  $SUDO git clone --depth=1 --branch "$REF" "$REPO_URL" "$DEST"
+fi
+
+# 4. run bootstrap, forwarding any extra args
 say "running bootstrap.sh $*"
 $SUDO chmod +x "$DEST/bootstrap.sh" "$DEST/config/motd/01-banner.sh"
 exec "$DEST/bootstrap.sh" "$@"