diff --git a/tests/main/snap-seccomp-blocks-tty-injection/task.yaml b/tests/main/snap-seccomp-blocks-tty-injection/task.yaml
index 2bdbfe020df..e839945cc38 100644
--- a/tests/main/snap-seccomp-blocks-tty-injection/task.yaml
+++ b/tests/main/snap-seccomp-blocks-tty-injection/task.yaml
@@ -24,6 +24,6 @@ execute: |
         apparmor_parser -r /var/lib/snapd/apparmor/profiles/snap.test-snapd-sh.sh
     fi
 
-    snap run test-snapd-sh.sh -c "\$SNAP_COMMON/test-tiocsti"   < /dev/tty1 2>&1 | MATCH 'normal TIOCSTI: -1 \(Operation not permitted\)'
-    snap run test-snapd-sh.sh -c "\$SNAP_COMMON/test-tiocsti"   < /dev/tty1 2>&1 | MATCH 'high-bit-set TIOCSTI: -1 \(Operation not permitted\)'
+    snap run test-snapd-sh.sh -c "\$SNAP_COMMON/test-tiocsti"   < /dev/tty1 2>&1 | MATCH 'normal TIOCSTI: -1 \((Operation not permitted|Permission denied)\)'
+    snap run test-snapd-sh.sh -c "\$SNAP_COMMON/test-tiocsti"   < /dev/tty1 2>&1 | MATCH 'high-bit-set TIOCSTI: -1 \((Operation not permitted|Permission denied)\)'
     snap run test-snapd-sh.sh -c "\$SNAP_COMMON/test-tioclinux" < /dev/tty1 2>&1 | MATCH 'ioctl\(0, TIOCLINUX, ...\) failed: Permission denied'
diff --git a/tests/main/snap-seccomp-blocks-tty-injection/test-tiocsti.c b/tests/main/snap-seccomp-blocks-tty-injection/test-tiocsti.c
index 8dd54958a23..b9b2ee56e3b 100644
--- a/tests/main/snap-seccomp-blocks-tty-injection/test-tiocsti.c
+++ b/tests/main/snap-seccomp-blocks-tty-injection/test-tiocsti.c
@@ -14,9 +14,17 @@ static int ioctl64(int fd, unsigned long nr, void *arg) {
 int main(void) {
   int res;
   char pushmeback = '#';
-  res = ioctl64(0, TIOCSTI, &pushmeback);
+
+  unsigned long syscallnr = TIOCSTI;
+  res = ioctl64(0, syscallnr, &pushmeback);
   printf("normal TIOCSTI: %d (%m)\n", res);
-  res = ioctl64(0, TIOCSTI | (1UL<<32), &pushmeback);
+
+#ifdef __LP64__
+  // this high bit check only works on 64bit systems, on 32bit it will fail:
+  // "error: left shift count >= width of type [-Werror=shift-count-overflow]"
+  syscallnr = TIOCSTI | (1UL<<32);
+#endif
+  res = ioctl64(0, syscallnr, &pushmeback);
   printf("high-bit-set TIOCSTI: %d (%m)\n", res);
   return res;
 }