diff --git a/Changes b/Changes
index dc88b9f08..4ee3ff8b7 100644
--- a/Changes
+++ b/Changes
@@ -313,6 +313,11 @@ Working version
 - #9367: Make bytecode and native-code backtraces agree.
   (Stephen Dolan, review by Gabriel Scherer)
 
+- #9428: Fix truncated exception backtrace for C->OCaml callbacks
+  on Power and Z System
+  (Xavier Leroy, review by Nicolás Ojeda Bär)
+
+
 OCaml 4.10 maintenance branch
 -----------------------------
 
diff --git a/runtime/power.S b/runtime/power.S
index 69e01fa7c..1933a10ed 100644
--- a/runtime/power.S
+++ b/runtime/power.S
@@ -410,8 +410,6 @@ FUNCTION(caml_raise_exception)
     /* Branch to handler */
         bctr
 .L121:
-        li      0, 0
-        stg     0, Caml_state(backtrace_pos)
         mr      27, 3           /* preserve exn bucket in callee-save reg */
                                 /* arg1: exception bucket, already in r3 */
         lg      4, Caml_state(last_return_address) /* arg2: PC of raise */
diff --git a/runtime/s390x.S b/runtime/s390x.S
index 0ae3f82ae..aab63e9b2 100644
--- a/runtime/s390x.S
+++ b/runtime/s390x.S
@@ -183,8 +183,6 @@ caml_raise_exception:
     /* Branch to handler */
         br      %r1;
 .L112:
-        lgfi    %r0, 0
-        stg     %r0, Caml_state(backtrace_pos)
         ldgr    %f15,%r2        /* preserve exn bucket in callee-save reg */
                                 /* arg1: exception bucket, already in r2 */
         lg      %r3, Caml_state(last_return_address) /* arg2: PC of raise */