diff --git a/devamlc.h b/devamlc.h
index 5c32f8d..eee8f7d 100644
--- a/devamlc.h
+++ b/devamlc.h
@@ -991,6 +991,7 @@ int devamlc (int class, int func, int device) {
         if (dc[dx].xmitenabled & BITMASK16(lx+1)) {
           int n, maxn;
           unsigned short qtop, qbot, qseg, qmask, qents;
+          short hasiac;         /* This buffer contains an escaped IAC */
           ea_t qentea, qcbea;
           n = 0;
           qcbea = dc[dx].baseaddr + lx*4;
@@ -1019,12 +1020,35 @@ int devamlc (int class, int func, int device) {
                precludes the use of TTY8BIT mode... */
 
             n = 0;
+            hasiac = 0;
             for (i=0; i < maxn; i++) {
               unsigned short utemp;
               utemp = get16mem(qentea);
-              qentea = (qentea & ~qmask) | ((qentea+1) & qmask);
+/*              qentea = (qentea & ~qmask) | ((qentea+1) & qmask); */
               //printf("Device %o, line %d, entry=%o (%c)\n", device, lx, utemp, utemp & 0x7f);
+#ifdef NOMASKAMLC
+              if (((utemp & 0xff) == 0xff) && (dc[dx].ctype[lx] != CT_SERIAL))
+              {
+                if (n != 0)
+                  break;          /* Clear the buffer before handling IAC */
+                else
+                {
+                  buf[n++] = 0xFF;
+                  buf[n++] = 0xFF;
+                  hasiac = 1;
+                  qentea = (qentea & ~qmask) | ((qentea+1) & qmask);
+                  break;          /* Now ship _just_ the IAC */
+                }
+              }
+              else
+              {
+                buf[n++] = utemp & 0xFF;
+                qentea = (qentea & ~qmask) | ((qentea+1) & qmask);
+              }
+#else
+              /* None of the IAC handling matters if we splatter parity */
               buf[n++] = utemp & 0x7F;
+#endif
             }
           } else {
 
@@ -1089,7 +1113,10 @@ int devamlc (int class, int func, int device) {
                  used and Unix buffers get full so writes can't
                  complete */
 
-              qtop = (qtop & ~qmask) | ((qtop+nw) & qmask);
+              if (hasiac)
+                qtop = (qtop & ~qmask) | ((qtop+1) & qmask);
+              else
+                qtop = (qtop & ~qmask) | ((qtop+nw) & qmask);
               put16io(qtop, qcbea);
               if (nw > maxxmit)
                 maxxmit = nw;
diff --git a/em.c b/em.c
index e39031d..fdb37d1 100644
--- a/em.c
+++ b/em.c
@@ -2383,8 +2383,8 @@ static ea_t apea(unsigned short *bitarg) {
     iwea = ea;
     ea = ip;
     TRACE(T_EAAP, " After indirect, AP ea = %o/%o, bit=%d  %s\n", ea>>16, ea & 0xFFFF, bit, searchloadmap(ea,' '));
-    if (ea & 0x80000000)
-      fault(POINTERFAULT, ea>>16, iwea);
+//    if (ea & 0x80000000)
+//      fault(POINTERFAULT, ea>>16, iwea);
   }
   if (bitarg != NULL)
     *bitarg = bit;
diff --git a/makefile b/makefile
index 5662e3a..29ca409 100644
--- a/makefile
+++ b/makefile
@@ -33,7 +33,7 @@ trace: $(em_deps) $(all_deps)
 
 # the fixed clock rate build is useful for making problems reproduceable.
 #
-# If the emulator crashes on a specific program, run it at the end of 
+# If the emulator crashes on a specific program, run it at the end of
 # PRIMOS.COMI to get a more consistent instruction count for the
 # failure, then enable tracing a little before that with -trace <IC - 100>
 
@@ -41,5 +41,12 @@ trace: $(em_deps) $(all_deps)
 fixed: $(em_deps) $(all_deps)
 	$(CC) -DREV=\"${REV}\" ${CFLAGS} -DFIXEDCLOCK -DNOIDLE -DFAST -O em.c -o em
 
+# Experimental "don't mask off the high bit on amlc lines" build
+#
+# Let's see if this is breaking e.g. ymodem file transfers.
+
+nomaskamlc: $(em_deps) $(all_deps)
+	$(CC) -DREV=\"${REV}\" -DNOMASKAMLC ${CFLAGS} -DNOTRACE -DFAST -O -Winline -Wno-return-type em.c -o em.nomaskamlc
+
 clean:
 	rm -f $(em_objs)