diff --git a/packages/hal/src/dispensers/f56/bills.ts b/packages/hal/src/dispensers/f56/bills.ts
index dad459c..299b688 100644
--- a/packages/hal/src/dispensers/f56/bills.ts
+++ b/packages/hal/src/dispensers/f56/bills.ts
@@ -77,13 +77,20 @@ export const bills: Record<string, BillConfig> = {
   },
   GTQ: {
     thickness: 0x0c,
+    // Every quetzal note is 156 x 67 mm — physically the same as USD and
+    // HNL, which accept 146–166 (±10). This table inherited lamassu's ±5
+    // window (151–161) with Q5/Q20 centred on 158, and a Tejo in GTQ rejected
+    // 5/5 notes on every Q100 dispense with F56 error 82 00 (bill length,
+    // long): the BDU read >161 mm on every pick, and the reject tray held
+    // single notes, not pairs — so it was the window, not a double-pick.
+    // Widened to match USD/HNL, mirroring lamassu-machine b1cc3622.
     lengths: {
-      5: [0xa3, 0x99],
-      10: [0xa1, 0x97],
-      20: [0xa3, 0x99],
-      50: [0xa1, 0x97],
-      100: [0xa1, 0x97],
-      200: [0xa1, 0x97],
+      5: [0xa6, 0x92],
+      10: [0xa6, 0x92],
+      20: [0xa6, 0x92],
+      50: [0xa6, 0x92],
+      100: [0xa6, 0x92],
+      200: [0xa6, 0x92],
     },
     polymer: false,
   },