diff --git a/docker-compose.prod.yml b/docker-compose.prod.yml
index bb098be..7127349 100644
--- a/docker-compose.prod.yml
+++ b/docker-compose.prod.yml
@@ -51,6 +51,19 @@ services:
     # there is no separate namespace, and runc REFUSES it ("not allowed in host network
     # namespace"). Reader liveness ping uses the HOST's setting instead — the booth host must
     # set net.ipv4.ping_group_range (see appliance-provisioning §7 / disk-os-hardening).
+    #
+    # USB PRINTER PASSTHROUGH. A USB ESC/POS printer (Rongta/Cashino) is the kernel `usblp` char
+    # device /dev/usb/lpN on the HOST — the container has its own /dev and can't see it (probeUsb
+    # open() → ENOENT → printer always "offline"). Two parts, both needed:
+    #   - bind-mount /dev/usb so the lpN NODES appear inside the container, and
+    #   - a device-cgroup rule permitting the usblp char major (180) so the kernel allows the
+    #     open(). `180:*` covers lp0/lp1/lp2… so a USB replug/boot-order renumber still works
+    #     (the printer's path can move; set Connection=USB + the matching /dev/usb/lpN in setup).
+    # (Bind-mounting the dir, not a single `devices:` node, is what survives renumbering.)
+    volumes:
+      - /dev/usb:/dev/usb
+    device_cgroup_rules:
+      - "c 180:* rmw"
     logging:
       driver: json-file
       options: