diff --git a/src/libsrc/fiber.pla b/src/libsrc/fiber.pla
index e84a663..ee95f7a 100644
--- a/src/libsrc/fiber.pla
+++ b/src/libsrc/fiber.pla
@@ -66,7 +66,8 @@ asm fbrSwap(saveVM, restoreVM)
     STA ESTK,Y
     DEY
     BPL -
-    LDY HWSP
+    TXA
+    TAY
 -   LDA $100,Y
     STA (DST),Y
     LDA (SRC),Y