diff --git a/library/ecp_curves.c b/library/ecp_curves.c
index f3ae509..ae82cb7 100644
--- a/library/ecp_curves.c
+++ b/library/ecp_curves.c
@@ -4926,10 +4926,13 @@
 
     RESET;
 
-    ADD_LAST; NEXT;
-    ADD_LAST; NEXT;
+    /* Use the reduction for the carry as well:
+     * 2^192 * last_carry = 2^64 * last_carry + last_carry mod P192
+     */
+    ADD_LAST; NEXT;                 // A0 += last_carry
+    ADD_LAST; NEXT;                 // A1 += last_carry
 
-    LAST;
+    LAST;                           // A2 += carry
 
     return 0;
 }