diff --git a/debian/daedalus-v4l2-dkms/build-deb.sh b/debian/daedalus-v4l2-dkms/build-deb.sh
index e0cea45c0..a78c517c3 100755
--- a/debian/daedalus-v4l2-dkms/build-deb.sh
+++ b/debian/daedalus-v4l2-dkms/build-deb.sh
@@ -16,7 +16,7 @@ set -euo pipefail
 
 UPSTREAM_COMMIT=f0d41867f60f5bf8dbfcc6cc16404d7d7eb90014
 PKGVER=0.1.0+r24+gf0d4186
-PKGREL=1  # reset for new upstream pin (3dd0eb0 — DAEMON-PPS H.264 SPS/PPS NAL synth)
+PKGREL=2  # postinst: autoinstall for every installed kernel with headers (#64)
 MODULE_NAME=daedalus_v4l2
 
 HERE=$(dirname "$(readlink -f "$0")")
@@ -78,7 +78,6 @@ set -e
 
 NAME=${MODULE_NAME}
 VERSION=${PKGVER}
-KERNELVER=\$(uname -r)
 
 # Yellow + bold ANSI for the warning so it stands out in apt's
 # stream of "Setting up" lines.  Disable colour on non-TTY.
@@ -101,29 +100,56 @@ if [ "\$1" = "configure" ]; then
 
     dkms add "\$NAME/\$VERSION" 2>/dev/null || true
 
-    # Don't let autoinstall failure mask the actual problem behind '|| true'.
-    # Run it, capture the result, then verify post-condition.
-    autoinstall_rc=0
-    dkms autoinstall "\$NAME/\$VERSION" || autoinstall_rc=\$?
+    # Enumerate every kernel whose headers are actually present
+    # (/lib/modules/<kver>/build resolves to a directory).  We iterate
+    # all of them — not just \$(uname -r) — so that installing this
+    # package after a kernel update covers the newly-installed kernel
+    # too, and so that a later kernel-headers install for a previously
+    # uncovered version gets picked up on dpkg-reconfigure.  Without
+    # this, autoinstall (which targets only the running kernel) leaves
+    # /dev/daedalus-v4l2 absent after a kernel switch + reboot
+    # (marfrit/marfrit-packages#64).
+    kvers=''
+    for d in /lib/modules/*/build; do
+        [ -d "\$d" ] || continue
+        k=\$(basename "\$(dirname "\$d")")
+        kvers="\$kvers \$k"
+    done
 
-    # Verify the module actually built + installed for the running kernel.
-    status=\$(dkms status -m "\$NAME" -v "\$VERSION" -k "\$KERNELVER" 2>/dev/null || true)
-    if ! printf '%s\\n' "\$status" | grep -q -E 'installed|loaded'; then
+    if [ -z "\$kvers" ]; then
         warn ""
-        warn "DKMS build did NOT land for kernel \$KERNELVER."
-        warn "  dkms status -m \$NAME -v \$VERSION -k \$KERNELVER:"
-        warn "    \$(printf '%s' "\$status" | head -1)"
-        warn ""
-        warn "Most likely cause: kernel headers package is missing."
-        warn "  Raspberry Pi OS / Pi 5:  apt install linux-headers-rpi-2712"
-        warn "  Debian generic:          apt install linux-headers-\$KERNELVER"
-        warn ""
-        warn "After installing headers, finish the install with:"
+        warn "No kernels with headers found under /lib/modules/*/build."
+        warn "Install kernel headers (e.g. linux-headers-rpi-2712 on Pi OS)"
+        warn "then finish with:"
         warn "  sudo dkms autoinstall \$NAME/\$VERSION"
-        warn "  sudo modprobe daedalus_v4l2"
+        exit 0
+    fi
+
+    failed=''
+    for k in \$kvers; do
+        dkms autoinstall -k "\$k" "\$NAME/\$VERSION" >/dev/null 2>&1 || true
+        s=\$(dkms status -m "\$NAME" -v "\$VERSION" -k "\$k" 2>/dev/null || true)
+        if ! printf '%s\\n' "\$s" | grep -q -E 'installed|loaded'; then
+            failed="\$failed \$k"
+        fi
+    done
+
+    if [ -n "\$failed" ]; then
         warn ""
-        warn "Until then daedalus_v4l2 will NOT be loadable and the"
-        warn "userspace daedalus-v4l2 daemon will have nothing to talk to."
+        warn "DKMS build did NOT land for kernel(s):\$failed"
+        warn ""
+        warn "Most likely cause: kernel headers missing for those versions."
+        warn "  Raspberry Pi OS / Pi 5:  apt install linux-headers-rpi-2712"
+        warn "  Debian generic:          apt install linux-headers-<version>"
+        warn ""
+        warn "After installing headers, finish with:"
+        for k in \$failed; do
+            warn "  sudo dkms autoinstall -k \$k \$NAME/\$VERSION"
+        done
+        warn "  sudo modprobe daedalus_v4l2  (after booting that kernel)"
+        warn ""
+        warn "Until then daedalus_v4l2 will NOT be loadable on those kernels"
+        warn "and the userspace daedalus-v4l2 daemon will have nothing to talk to."
     fi
 fi
 
diff --git a/debian/daedalus-v4l2-dkms/debian/changelog b/debian/daedalus-v4l2-dkms/debian/changelog
index 763bde3c2..e78f9978b 100644
--- a/debian/daedalus-v4l2-dkms/debian/changelog
+++ b/debian/daedalus-v4l2-dkms/debian/changelog
@@ -1,3 +1,18 @@
+daedalus-v4l2-dkms (0.1.0+r24+gf0d4186-2) bookworm trixie; urgency=medium
+
+  * postinst: autoinstall for every installed kernel with headers, not
+    just the running one.  Previously `dkms autoinstall $NAME/$VERSION`
+    built only against `$(uname -r)`, so installing the package on
+    kernel A and then rebooting into a separately-installed kernel B
+    left /lib/modules/B/updates/dkms/ empty — /dev/daedalus-v4l2 absent,
+    daedalus daemon nothing to talk to, browser/VAAPI silently falling
+    back to software with no obvious diagnostic.  Now we enumerate every
+    /lib/modules/*/build that resolves to a real directory and run
+    `dkms autoinstall -k <kver>` for each, reporting per-kernel failure
+    only when headers are missing.  Closes #64.
+
+ -- Markus Fritsche <mfritsche@reauktion.de>  Thu, 21 May 2026 09:30:00 +0000
+
 daedalus-v4l2-dkms (0.1.0+r24+gf0d4186-1) bookworm trixie; urgency=medium
 
   * Bump to f0d4186 — per-ctx vb2 lock fix.  daedalus_queue_init now