diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
index 5d2b7ba94d..835341457d 100644
--- a/pc-bios/s390-ccw/main.c
+++ b/pc-bios/s390-ccw/main.c
@@ -281,7 +281,7 @@ static void probe_boot_device(void)
     sclp_print("Could not find a suitable boot device (none specified)\n");
 }
 
-int main(void)
+void main(void)
 {
     sclp_setup();
     css_setup();
@@ -294,5 +294,4 @@ int main(void)
     }
 
     panic("Failed to load OS from hard disk\n");
-    return 0; /* make compiler happy */
 }
diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
index 79db69ff54..b88e0550ab 100644
--- a/pc-bios/s390-ccw/s390-ccw.h
+++ b/pc-bios/s390-ccw/s390-ccw.h
@@ -57,6 +57,7 @@ void write_subsystem_identification(void);
 void write_iplb_location(void);
 extern char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
 unsigned int get_loadparm_index(void);
+void main(void);
 
 /* sclp.c */
 void sclp_print(const char *string);