diff --git a/hbbytecode/src/lib.rs b/hbbytecode/src/lib.rs
index 78298bb..8a937b1 100644
--- a/hbbytecode/src/lib.rs
+++ b/hbbytecode/src/lib.rs
@@ -80,9 +80,6 @@ pub struct ParamBBB(pub u8, pub u8, pub u8);
 #[repr(packed)]
 pub struct ParamBBDH(pub u8, pub u8, pub u64, pub u16);
 
-#[repr(packed)]
-pub struct ParamBBDB(pub u8, pub u8, pub u64, pub u8);
-
 #[repr(packed)]
 pub struct ParamBBD(pub u8, pub u8, pub u64);
 
@@ -97,7 +94,6 @@ pub struct ParamBD(pub u8, pub u64);
 pub unsafe trait OpParam {}
 unsafe impl OpParam for ParamBBBB {}
 unsafe impl OpParam for ParamBBB {}
-unsafe impl OpParam for ParamBBDB {}
 unsafe impl OpParam for ParamBBDH {}
 unsafe impl OpParam for ParamBBD {}
 unsafe impl OpParam for ParamBB {}
diff --git a/spec.md b/spec.md
index b70ca58..c32e6eb 100644
--- a/spec.md
+++ b/spec.md
@@ -19,7 +19,6 @@
 | BBBB | 32 bits |
 | BBB  | 24 bits |
 | BBDH | 96 bits |
-| BBDB | 88 bits |
 | BBD  | 80 bits |
 |  BB  | 16 bits |
 |  BD  | 72 bits |