diff --git a/kernel/inthndlr.c b/kernel/inthndlr.c
index 7af35f5..3e1905a 100644
--- a/kernel/inthndlr.c
+++ b/kernel/inthndlr.c
@@ -434,10 +434,26 @@ dispatch:
   }
   /* Clear carry by default for these functions */
 
-  /* see PATCH TE 5 jul 04 explanation at end */
-  if (ErrorMode && lr.AH > 0x0c && lr.AH != 0x30 && lr.AH != 0x59)
+  /* We force clear the near fnodes,
+     On a normal int21h entry these are unused, so should already
+     be clear, thus this code is effectively redundant.
+     However when re-entering int21h, such as a device driver
+     (e.g. shsufdrv), the fnodes may contain the values of the
+     in progress call; as long as the driver/tsr causing the
+     reentrancey saves and restores the SDA across the call then
+     any changes we do (ie clearing these) should go unnoticed
+     and if the cause of the reentrancy does not save/restore the
+     SDA then the caller should expected the unexpected.
+     Failure to do this will at a minimal result in the extra
+     output indicating fnodes not 0 (and possibly clearing at end
+     of call) when the re-entered int21h call completes, but could
+     result in the re-entered call to fail with no free near fnodes
+     if both are already in use by the original int21h call (?bug 1879?).
+     See also PATCH TE 5 jul 04 explanation at end 
+   */
+  if (/*ErrorMode && */lr.AH > 0x0c && lr.AH != 0x30 && lr.AH != 0x59)
   {
-    ErrorMode = 0;
+    /*if (ErrorMode)*/ ErrorMode = 0;
     fnode[0].f_count = 0;    /* don't panic - THEY ARE unused !! */
     fnode[1].f_count = 0;
   }