diff --git a/docs/design.md b/docs/design.md
index 311af93..2d4eb30 100644
--- a/docs/design.md
+++ b/docs/design.md
@@ -80,6 +80,8 @@ A few overlays need special handling:
 - Just off a panel, the cursor stays on that panel's plane within `POINTER_EDGE_REACH`, so resize margins and window controls just outside the panel are reachable.
 - While the left button is held, the cursor keeps the distance it had at the press and stops re-testing collisions, so dragging past a panel's edge doesn't make it jump.
 
+Replacing a loaded driver's files, as re-running the installer used to do, leaves SteamVR honoring the virtual controller's hand role but not its laser claim: the dashboard pointer stays unassigned until SteamVR restarts. The driver installer now leaves an unchanged driver in place.
+
 `dashboard.laserRayWidthScale` controls the beam's width, but SteamVR only applies a change from its own settings screen or at restart, so it can't be switched per device while running.
 
 ### Handing the laser back and forth
diff --git a/pointer/driver/install.sh b/pointer/driver/install.sh
index 638e6d1..95bef34 100755
--- a/pointer/driver/install.sh
+++ b/pointer/driver/install.sh
@@ -18,13 +18,21 @@ reg='/opt/steamvr/bin/linuxarm64/vrpathreg'
 case ${1:-install} in
   install)
     "$root/scripts/sync.sh" >/dev/null
+    # Replacing the files of a driver SteamVR has loaded leaves its input bindings in a bad
+    # state (the 3D mouse no longer gets the laser) until SteamVR restarts, so an unchanged
+    # driver is left alone.
     "$frame" --host "set -e; test -f $src/build/driver_ft_pointer.so
-rm -rf $dest; mkdir -p $dest/bin/linuxarm64
-cp -r $src/ft_pointer/. $dest/
-cp $src/build/driver_ft_pointer.so $dest/bin/linuxarm64/
+rm -rf $dest.new; mkdir -p $dest.new/bin/linuxarm64
+cp -r $src/ft_pointer/. $dest.new/
+cp $src/build/driver_ft_pointer.so $dest.new/bin/linuxarm64/
+if [ -d $dest ] && diff -r -q $dest $dest.new >/dev/null; then
+  rm -rf $dest.new; echo 'driver unchanged'
+else
+  rm -rf $dest; mv $dest.new $dest
+  echo 'installed; restart SteamVR to load it'
+fi
 LD_LIBRARY_PATH=/opt/steamvr/bin/linuxarm64 $reg adddriver $dest
-LD_LIBRARY_PATH=/opt/steamvr/bin/linuxarm64 $reg show | grep -A3 -i 'external'
-echo 'installed; restart SteamVR to load it'" ;;
+LD_LIBRARY_PATH=/opt/steamvr/bin/linuxarm64 $reg show | grep -A3 -i 'external'" ;;
   uninstall)
     "$frame" --host "LD_LIBRARY_PATH=/opt/steamvr/bin/linuxarm64 $reg removedriver $dest; rm -rf $dest; echo 'removed; restart SteamVR to unload it'" ;;
   send)