diff --git a/src/kernel/core/real_time_clock.c b/src/kernel/core/real_time_clock.c
index cb6ba55751..e426f47996 100644
--- a/src/kernel/core/real_time_clock.c
+++ b/src/kernel/core/real_time_clock.c
@@ -57,7 +57,7 @@ rtc_hw_to_system(void)
 
 
 bigtime_t
-rtc_system_time_offset(void)
+rtc_boot_time(void)
 {
 	return sRealTimeData->system_time_offset;
 }
@@ -141,7 +141,6 @@ real_time_clock(void)
 bigtime_t
 real_time_clock_usecs(void)
 {
-	// ToDo: implement me - they might be used directly from libroot/os/time.c
 	return sRealTimeData->system_time_offset + system_time();
 }
 
@@ -176,12 +175,12 @@ _user_set_timezone(time_t timezoneOffset, bool daylightSavingTime)
 	if (geteuid() != 0)
 		return B_NOT_ALLOWED;
 
-	TRACE(("old system_time_offset %Ld\n", sRealTimeData->system_time_offset));
+	TRACE(("old system_time_offset %Ld old %Ld new %Ld gmt %d\n", sRealTimeData->system_time_offset, sTimezoneOffset, offset, sIsGMT));
 
 	// We only need to update our time offset if the hardware clock
 	// does not run in the local timezone.
 	// Since this is shared data, we need to update it atomically.
-	if (sIsGMT)
+	if (!sIsGMT)
 		atomic_add64(&sRealTimeData->system_time_offset, sTimezoneOffset - offset);
 
 	sTimezoneOffset = offset;
diff --git a/src/kernel/core/shutdown.c b/src/kernel/core/shutdown.c
index a5bd883c16..1eb40555b7 100644
--- a/src/kernel/core/shutdown.c
+++ b/src/kernel/core/shutdown.c
@@ -25,5 +25,8 @@ shutdown(bool reboot)
 status_t
 _user_shutdown(bool reboot)
 {
+	if (geteuid() != 0)
+		return B_NOT_ALLOWED;
 	return shutdown(reboot);
 }
+
diff --git a/src/kernel/core/system_info.c b/src/kernel/core/system_info.c
index 7faaa5c2b0..efd15da5a5 100644
--- a/src/kernel/core/system_info.c
+++ b/src/kernel/core/system_info.c
@@ -38,7 +38,7 @@ _get_system_info(system_info *info, size_t size)
 	// - max_teams
 	// - used_teams
 
-	info->boot_time = rtc_system_time_offset();
+	info->boot_time = rtc_boot_time();
 	info->cpu_count = smp_get_num_cpus();
 	info->used_ports = port_used_ports();
 	info->max_ports = port_max_ports();