diff --git a/libguile/vm-engine.c b/libguile/vm-engine.c
index e574eacab..cb5af2487 100644
--- a/libguile/vm-engine.c
+++ b/libguile/vm-engine.c
@@ -2783,15 +2783,15 @@ VM_NAME (scm_i_thread *thread, struct scm_vm *vp,
       NEXT (3);
     }
 
-  /* make-array dst:12 type:12 _:8 fill:12 bounds:12
+  /* make-array dst:8 type:8 fill:8 _:8 bounds:24
    *
    * Make a new array with TYPE, FILL, and BOUNDS, storing it in DST.
    */
-  VM_DEFINE_OP (106, make_array, "make-array", OP2 (U8_U12_U12, X8_U12_U12) | OP_DST)
+  VM_DEFINE_OP (106, make_array, "make-array", OP2 (U8_U8_U8_U8, X8_U24) | OP_DST)
     {
-      scm_t_uint16 dst, type, fill, bounds;
-      UNPACK_12_12 (op, dst, type);
-      UNPACK_12_12 (ip[1], fill, bounds);
+      scm_t_uint8 dst, type, fill, bounds;
+      UNPACK_8_8_8 (op, dst, type, fill);
+      UNPACK_24 (ip[1], bounds);
       SYNC_IP ();
       LOCAL_SET (dst, scm_make_typed_array (LOCAL_REF (type), LOCAL_REF (fill),
                                             LOCAL_REF (bounds)));
diff --git a/module/system/vm/assembler.scm b/module/system/vm/assembler.scm
index 8bbe1d90e..ca6ad02e9 100644
--- a/module/system/vm/assembler.scm
+++ b/module/system/vm/assembler.scm
@@ -398,12 +398,6 @@ later by the linker."
        ((U8_L24 a label)
         (record-label-reference asm label)
         (emit asm a))
-       ((U8_U8_I16 a b imm)
-        (emit asm (pack-u8-u8-u16 a b (object-address imm))))
-       ((U8_U12_U12 a b)
-        (emit asm (pack-u8-u12-u12 a b c)))
-       ((U8_U8_U8_U8 a b c d)
-        (emit asm (pack-u8-u8-u8-u8 a b c d)))
        ((U32 a)
         (emit asm a))
        ((I32 imm)
@@ -432,8 +426,6 @@ later by the linker."
         (emit asm 0))
        ((X8_U24 a)
         (emit asm (pack-u8-u24 0 a)))
-       ((X8_U12_U12 a b)
-        (emit asm (pack-u8-u12-u12 0 a b)))
        ((X8_L24 label)
         (record-label-reference asm label)
         (emit asm 0))
diff --git a/module/system/vm/disassembler.scm b/module/system/vm/disassembler.scm
index 248b44e14..3d8de82f2 100644
--- a/module/system/vm/disassembler.scm
+++ b/module/system/vm/disassembler.scm
@@ -110,19 +110,6 @@
           ((U8_L24)
            #'((logand word #xff)
               (unpack-s24 (ash word -8))))
-          ((U8_U8_I16)
-           #'((logand word #xff)
-              (logand (ash word -8) #xff)
-              (ash word -16)))
-          ((U8_U12_U12)
-           #'((logand word #xff)
-              (logand (ash word -8) #xfff)
-              (ash word -20)))
-          ((U8_U8_U8_U8)
-           #'((logand word #xff)
-              (logand (ash word -8) #xff)
-              (logand (ash word -16) #xff)
-              (ash word -24)))
           ((U32)
            #'(word))
           ((I32)
@@ -141,9 +128,6 @@
            #'((unpack-s32 word)))
           ((X8_U24)
            #'((ash word -8)))
-          ((X8_U12_U12)
-           #'((logand (ash word -8) #xfff)
-              (ash word -20)))
           ((X8_L24)
            #'((unpack-s24 (ash word -8))))
           ((B1_X7_L24)