diff --git a/libc/kernel/arch-arm/asm/mc146818rtc.h b/libc/kernel/arch-arm/asm/mc146818rtc.h
index 5a86724..a389401 100644
--- a/libc/kernel/arch-arm/asm/mc146818rtc.h
+++ b/libc/kernel/arch-arm/asm/mc146818rtc.h
@@ -7,20 +7,25 @@
  ***   structures, and macros generated from the original header, and thus,
  ***   contains no copyrightable information.
  ***
+ ***   To edit the content of this header, modify the corresponding
+ ***   source file (e.g. under external/kernel-headers/original/) then
+ ***   run bionic/libc/kernel/tools/update_all.py
+ ***
+ ***   Any manual change here will be lost the next time this script will
+ ***   be run. You've been warned!
+ ***
  ****************************************************************************
  ****************************************************************************/
 #ifndef _ASM_MC146818RTC_H
 #define _ASM_MC146818RTC_H
-
 #include <asm/arch/irqs.h>
 #include <asm/io.h>
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #ifndef RTC_PORT
 #define RTC_PORT(x) (0x70 + (x))
 #define RTC_ALWAYS_BCD 1  
 #endif
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define CMOS_READ(addr) ({  outb_p((addr),RTC_PORT(0));  inb_p(RTC_PORT(1));  })
 #define CMOS_WRITE(val, addr) ({  outb_p((addr),RTC_PORT(0));  outb_p((val),RTC_PORT(1));  })
-
 #endif