diff --git a/src/mame/drivers/cb2001.c b/src/mame/drivers/cb2001.c
index 4a1017d9767..1056ae1de9d 100644
--- a/src/mame/drivers/cb2001.c
+++ b/src/mame/drivers/cb2001.c
@@ -46,18 +46,18 @@ In test mode (c) is 2000
 #define xxxx 0x90 /* Unknown */
 
 static const UINT8 cb2001_decryption_table[256] = {
-	0xe8,xxxx,0x94,xxxx,xxxx,0x61,xxxx,xxxx, 0x3c,xxxx,xxxx,xxxx,xxxx,xxxx,xxxx,xxxx, /* 00 */
-//    pppp      ????           ????            pppp
-	xxxx,xxxx,xxxx,xxxx,xxxx,xxxx,xxxx,xxxx, 0x32,xxxx,0xa0,xxxx,0x3a,xxxx,0x89,xxxx, /* 10 */
-//                                             pppp     ????       pppp      pppp ????
-	xxxx,0x8e,xxxx,0x0f,xxxx,0x49,0xb2,xxxx, xxxx,xxxx,xxxx,0x75,xxxx,xxxx,xxxx,xxxx, /* 20 */
-//         !!!!      ????      ???? ????                      pppp
+	0xe8,xxxx,0x94,xxxx,0x80,0x61,xxxx,xxxx, 0x3c,xxxx,xxxx,xxxx,xxxx,xxxx,xxxx,xxxx, /* 00 */
+//    pppp      ????      ???? ????            pppp
+	xxxx,xxxx,xxxx,xxxx,xxxx,xxxx,xxxx,xxxx, 0x32,xxxx,0xa0,0xd3,0x3a,xxxx,0x89,xxxx, /* 10 */
+//                                             pppp     ????  pppp pppp      pppp ????
+	xxxx,0x8e,xxxx,0x0f,xxxx,0x49,0xb5,xxxx, xxxx,xxxx,xxxx,0x75,xxxx,xxxx,xxxx,xxxx, /* 20 */
+//         !!!!      ????      ???? pppp                      pppp
 	0x9d,xxxx,xxxx,xxxx,xxxx,xxxx,0xbe,xxxx, xxxx,xxxx,0x74,xxxx,xxxx,0xa6,0xbf,0x74, /* 30 */
 //    ????                          ????                 ????           ???? ???? pppp
 	xxxx,0xea,xxxx,xxxx,xxxx,0xb0,xxxx,xxxx, xxxx,0xa2,xxxx,xxxx,xxxx,xxxx,xxxx,xxxx, /* 40 */
 //         !!!!                gggg                 pppp
-	xxxx,xxxx,0x2c,xxxx,xxxx,xxxx,0x42,xxxx, xxxx,xxxx,xxxx,xxxx,0xeb,xxxx,xxxx,xxxx, /* 50 */
-//              pppp                ????                           pppp
+	xxxx,xxxx,0x2c,xxxx,xxxx,xxxx,0x42,0xc0, xxxx,xxxx,xxxx,xxxx,0xeb,xxxx,xxxx,xxxx, /* 50 */
+//              pppp                ???? pppp                      pppp
 	xxxx,xxxx,xxxx,xxxx,0x22,xxxx,xxxx,xxxx, xxxx,0xa5,xxxx,xxxx,xxxx,0xbb,0xba,xxxx, /* 60 */
 //                        pppp                      ????                pppp gggg
 	0xc3,xxxx,0x02,xxxx,xxxx,xxxx,0x24,xxxx, 0x72,xxxx,0xf2,xxxx,xxxx,0x43,xxxx,xxxx, /* 70 */
@@ -100,6 +100,7 @@ cmast91:                      cb2001:
 -------------------------------------------------
 
 cmv4                          cb2001                     (en -> de)
+
 029f ld b,$fc                 
 02a1 call $0c38               e0239 call 0e30b8h
 02a4 ld hl,$d023              e023d mov ix,90h
@@ -145,8 +146,11 @@ cmv4                          cb2001                     (en -> de)
   .                             e670f be 0e6712h
   4ac8 ret nz                   e6711 ret                (70 -> c3)
 
-  4ac9 ld hl,($d61a)            e671c mov al,b ptr[bw]
-  4acc ld a,(hl)                .
+  4ac9 ld hl,($d61a)            e6712 mov bw,w ptr[72fh]
+  .                             e6716 OB DB                         ?????????
+  .                             e6718 bne 0e671bh
+  .                             e671a ret
+  4acc ld a,(hl)                e671b mov al,b ptr ss[bw](ce -> 36) (e0 -> 8a) not sure about the prefix
   4acd inc hl                   e671e inc bw             (7d -> 43)
   4ace cp $f0                   e671f cmp al,0f0h
   4ad0 jr nc,$4b14              e6721 bnc 0e676fh        (8c -> 73)
@@ -154,11 +158,34 @@ cmv4                          cb2001                     (en -> de)
   4add sub $50                  e672f sub al,50h         (52 -> 2c)
   4adf cp $50                   e6731 cmp al,50h
   4ae1 jr c,$4ae7               e6733 bc 0e6739          (78 -> 72)
-  4ae3 ld b,$04                 e6735 26 04
+  4ae3 ld b,$04                 e6735 mov ch,4h          (26 -> b5)
   4ae5 sub $50                  e6737 sub al,50h
-  4ae7 ld c,a                   e6739 mov cl,al          (e0 -> 8a)
+  4ae7 ld c,a                   e6739 mov cl,al
   4ae8 and $0f                  e673b and al,0fh         (76 -> 24)
   4aea add a,a                  e673d add al,al
+  4aeb ld e,a                   .
+  4aec ld d,$00                 e673f mov ah,0h
+  4aee ld hl,$4b42              e6741 mov bw,67ab
+  4af1 add hl,de                e6744 add bw,aw
+  4af2 ld e,(hl)                e6746 mov bw,w ptr ss[bw]           not sure the prefix
+  4af3 inc hl                   .
+  4af4 ld d,(hl)                .
+  4af5 ld a,c                   .
+  4af6 and $f0                  e6749 and cl,f0h         (ce -> 80) probably, maybe 82
+  4af8 jr z,$4b05               e674c be 0e6753
+  4afa rrca                     .
+  4afb rrca                     .
+  4afc rrca                     .
+  4afd rrca                     e674e ror cl,4h          (57 -> c0)
+  4afe srl d                    .
+  4b00 rr e                     e6751 shr bw,cl          (1b -> d3)
+  4b02 dec a                    .
+  4b03 jr nz,$4afe              .
+  4b05 ld a,b                   e6753 mov al,ch
+  .                             e6755 mov dw,23h
+  4b06 out ($03),a              e6758 out dw,al
+
+
 
 
 -------------------------------------------------