diff --git a/resources/definitions/ultimaker_original.def.json b/resources/definitions/ultimaker_original.def.json
index bb6a64d8dc..bb21e4b82e 100644
--- a/resources/definitions/ultimaker_original.def.json
+++ b/resources/definitions/ultimaker_original.def.json
@@ -20,7 +20,7 @@
             "0": "ultimaker_original_extruder_0"
         },
         "firmware_file": "MarlinUltimaker-{baudrate}.hex",
-        "firmware_hbk_file": "MarlinUltimaker-HKB-{baudrate}.hex"
+        "firmware_hbk_file": "MarlinUltimaker-HBK-{baudrate}.hex"
     },
 
     "overrides": {
diff --git a/resources/definitions/ultimaker_original_dual.def.json b/resources/definitions/ultimaker_original_dual.def.json
index c6002ef396..1ffb6e840b 100644
--- a/resources/definitions/ultimaker_original_dual.def.json
+++ b/resources/definitions/ultimaker_original_dual.def.json
@@ -20,7 +20,7 @@
             "1": "ultimaker_original_dual_2nd"
         },
         "firmware_file": "MarlinUltimaker-{baudrate}-dual.hex",
-        "firmware_hbk_file": "MarlinUltimaker-HKB-{baudrate}-dual.hex",
+        "firmware_hbk_file": "MarlinUltimaker-HBK-{baudrate}-dual.hex",
         "first_start_actions": ["UMOUpgradeSelection", "UMOCheckup", "BedLevel"],
         "supported_actions": ["UMOUpgradeSelection", "UMOCheckup", "BedLevel", "UpgradeFirmware"]
     },