diff --git a/tool/run/boot_dir/fiasco b/tool/run/boot_dir/fiasco
index 3e9e518c5..52ed15d15 100644
--- a/tool/run/boot_dir/fiasco
+++ b/tool/run/boot_dir/fiasco
@@ -59,6 +59,11 @@ proc bin_dir { } {
 set fiasco_serial_esc_arg "-serial_esc "
 
 
+proc run_boot_string { } {
+	return "L4 Bootstrapper"
+}
+
+
 ##
 # Populate boot directory with binaries on fiasco
 #
diff --git a/tool/run/boot_dir/foc b/tool/run/boot_dir/foc
index 62b2b6be1..ce4500fd2 100644
--- a/tool/run/boot_dir/foc
+++ b/tool/run/boot_dir/foc
@@ -240,6 +240,11 @@ proc run_boot_dir_arm {binaries} {
 }
 
 
+proc run_boot_string { } {
+	return "L4 Bootstrapper"
+}
+
+
 ##
 # Populate boot directory with binaries on fiasco.OC
 #
diff --git a/tool/run/boot_dir/hw b/tool/run/boot_dir/hw
index f6d9b96c6..8213aff43 100644
--- a/tool/run/boot_dir/hw
+++ b/tool/run/boot_dir/hw
@@ -10,6 +10,11 @@ proc run_boot_dir_hook { } {
 }
 
 
+proc run_boot_string { } {
+	return "kernel initialized"
+}
+
+
 ##
 # Populate boot directory with binaries on hw
 #
diff --git a/tool/run/boot_dir/nova b/tool/run/boot_dir/nova
index 7057df455..ae5c8fbcd 100644
--- a/tool/run/boot_dir/nova
+++ b/tool/run/boot_dir/nova
@@ -24,6 +24,11 @@ proc nova_external { } {
 }
 
 
+proc run_boot_string { } {
+	return "NOVA Microhypervisor"
+}
+
+
 ##
 # Populate directory with binaries on NOVA
 #
diff --git a/tool/run/boot_dir/okl4 b/tool/run/boot_dir/okl4
index 6036eebb1..e24789d19 100644
--- a/tool/run/boot_dir/okl4
+++ b/tool/run/boot_dir/okl4
@@ -101,6 +101,11 @@ set weaver_xml_template {
 }
 
 
+proc run_boot_string { } {
+	return "OKL4 -"
+}
+
+
 ##
 # Populate directory with binaries on OKL4
 #
diff --git a/tool/run/boot_dir/pistachio b/tool/run/boot_dir/pistachio
index 8b6ae51c1..b91ab311f 100644
--- a/tool/run/boot_dir/pistachio
+++ b/tool/run/boot_dir/pistachio
@@ -63,6 +63,11 @@ proc kernel_external { } {
 }
 
 
+proc run_boot_string { } {
+	return "L4Ka::Pistachio -"
+}
+
+
 ##
 # Populdate boot directory with binaries on pistachio
 #
diff --git a/tool/run/log/serial b/tool/run/log/serial
index 65a3b6bfb..e4ddf3eac 100644
--- a/tool/run/log/serial
+++ b/tool/run/log/serial
@@ -22,21 +22,25 @@ proc log_serial_cmd { } {
 proc run_log { wait_for_re timeout_value } {
 	global output_spawn_id
 
-	set timeout 60
-	while {true} {
-		eval spawn [log_serial_cmd]
-		set output_spawn_id $spawn_id
-		expect {
-			"Genode \[0-9]\[0-9]\.\[0-9]\[0-9]"  {
-				wait_for_output $wait_for_re $timeout_value $output_spawn_id;
-				return true;
-			}
-			eof          { continue; }
-			timeout      {
-				puts stderr "Boot process timed out";
-				close;
-				return false;
-			}
+	set kernel_msg [run_boot_string]
+
+	eval spawn [log_serial_cmd]
+	set output_spawn_id $spawn_id
+
+	set timeout 210
+	expect {
+		$kernel_msg { }
+		eof         {
+			puts stderr "Serial command process died unexpectedly"
+			return false
+		}
+		timeout     {
+			puts stderr "Boot process timed out"
+			close
+			return false
 		}
 	}
+
+	wait_for_output $wait_for_re $timeout_value $output_spawn_id
+	return true
 }
diff --git a/tool/run/run b/tool/run/run
index 1a346769b..792fa4c81 100755
--- a/tool/run/run
+++ b/tool/run/run
@@ -489,6 +489,10 @@ proc wait_for_output { wait_for_re timeout_value running_spawn_id } {
 ## Fall-back implementations of all run module procedures
 ##
 
+##
+# Dummy boot_string procedure
+proc run_boot_string { } { return ""; }
+
 ##
 # Dummy boot_dir maodule
 proc run_boot_dir { } { return true; }