diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 1522a16..b4fc004 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -5284,8 +5284,11 @@
             /* The remaining input chars are ignored if the callback
                chooses to skip the input */
         case 1:
+            q -= 2;
+            if (consumed)
+                goto End;
             errmsg = "unexpected end of data";
-            startinpos = ((const char *)q) - 2 - starts;
+            startinpos = ((const char *)q) - starts;
             endinpos = ((const char *)e) - starts;
             break;
         case 2: