diff --git a/src/BlueSCSI.cpp b/src/BlueSCSI.cpp
index 0773101..482b13a 100644
--- a/src/BlueSCSI.cpp
+++ b/src/BlueSCSI.cpp
@@ -1180,8 +1180,7 @@ void loop()
 
   LOGHEX(cmd[0]);
   // Command length selection, reception
-  static const int cmd_class_len[8]={6,10,10,6,6,12,6,6};
-  len = cmd_class_len[cmd[0] >> 5];
+  len = cdb_len_lookup[cmd[0]];
   cmd[1] = readHandshake(); LOG(":");LOGHEX(cmd[1]);
   cmd[2] = readHandshake(); LOG(":");LOGHEX(cmd[2]);
   cmd[3] = readHandshake(); LOG(":");LOGHEX(cmd[3]);
diff --git a/src/BlueSCSI.h b/src/BlueSCSI.h
index 3e6c7bb..1d6eaff 100644
--- a/src/BlueSCSI.h
+++ b/src/BlueSCSI.h
@@ -325,5 +325,19 @@ typedef __attribute__((aligned(4))) struct _SCSI_DEVICE
   uint8_t       m_sector_offset;          // optical sector offset for missing sync header
 } SCSI_DEVICE;
 
+static byte cdb_len_lookup[] = {
+  6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+  10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+  10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+  10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+  10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+  10,10,10,10,10,10,10,10,10,10,10,10,10,16,16,16,16,16,16,16,16,
+  16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,
+  16,16,16,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,
+  12,12,12,12,12,12,12,12,12,12,12,12,12,12,10,10,10,10,10,10,10,
+  10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+  10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+  10,10,10,10,10,10,10,10,10,10,10,10,10,10
+};
 
-#endif
\ No newline at end of file
+#endif