diff --git a/ALTAIR/altair_dsk.c b/ALTAIR/altair_dsk.c
index 64ef739c..1d1f092c 100644
--- a/ALTAIR/altair_dsk.c
+++ b/ALTAIR/altair_dsk.c
@@ -218,8 +218,8 @@ int32 dsk10(int32 io, int32 data)
     cur_disk = data & 0x0F;
     if (data & 0x80) {
         cur_flags[cur_disk] = 0;                        /* Disable drive */
-        cur_sect[cur_disk = 0377];
-        cur_byte[cur_disk = 0377];
+        cur_sect[cur_disk] = 0377;
+        cur_byte[cur_disk] = 0377;
         return (0);
     }
     cur_flags[cur_disk] = 0x1A;                         /* Enable: head move true */
diff --git a/I1401/i1401_sys.c b/I1401/i1401_sys.c
index bab227f3..94976277 100644
--- a/I1401/i1401_sys.c
+++ b/I1401/i1401_sys.c
@@ -402,7 +402,7 @@ if (op >= 64)                                           /* successful? */
     return SCPE_ARG;
 val[0] = op | WM;                                       /* store opcode */
 cptr = get_glyph (cptr, gbuf, 0);                       /* get addr or d */
-if (((op_table[op] && IO) && (get_io (gbuf, &val[1]) == SCPE_OK)) ||
+if (((op_table[op] & IO) && (get_io (gbuf, &val[1]) == SCPE_OK)) ||
      (get_addr (gbuf, &val[1]) == SCPE_OK)) {
         cptr = get_glyph (cptr, gbuf, 0);               /* get addr or d */
         if (get_addr (gbuf, &val[4]) == SCPE_OK) {