diff --git a/lib/openmsx/share/scripts/fail_after.tcl b/lib/openmsx/share/scripts/fail_after.tcl
index 6ac9783..e858ef5 100644
--- a/lib/openmsx/share/scripts/fail_after.tcl
+++ b/lib/openmsx/share/scripts/fail_after.tcl
@@ -65,8 +65,14 @@ proc fail_after { timeout {time_unit "time"} {fail_id "fail_after"} {fail_code 2
 proc fail_after_reboot_watchdog {} {
 	global fail_after_boot_timeout
 	if {$fail_after_boot_timeout != 0} {
-		fail_after $fail_after_boot_timeout realtime err_boot 124
-		after boot "fail_after_reboot_watchdog"
+		if {[catch {fail_after $fail_after_boot_timeout realtime err_boot 124} err_msg]} {
+			puts stderr "error: $err_msg"
+			fail_after_exit fail_after_reboot_install_error 1
+		}
+		if {[catch {after boot "fail_after_reboot_watchdog"} err_msg]} {
+			puts stderr "error: $err_msg"
+			fail_after_exit fail_after_reboot_cycle_error 1
+		}
 	}
 }