diff --git a/core/Makefile b/core/Makefile

index 33ad7e9..49ba474 100644

--- a/core/Makefile

+++ b/core/Makefile

@@ -63,7 +63,7 @@ PREPCORE = ../lzo/prepcore

 # official release.  Otherwise, substitute a hex string that is pretty much

 # guaranteed to be unique to be unique from build to build.

 ifndef HEXDATE

-HEXDATE := $(shell $(PERL) ../now.pl $(SRCS))

+HEXDATE := $(shell $(PERL) ../now.pl $(ALLSRC))

 endif

 ifndef DATE

 DATE    := $(shell sh ../gen-id.sh $(VERSION) $(HEXDATE))

diff --git a/libinstaller/bin2c.pl b/libinstaller/bin2c.pl

index 07c11dd..2864488 100755

--- a/libinstaller/bin2c.pl

+++ b/libinstaller/bin2c.pl

@@ -71,8 +71,4 @@ if ($align != 0) {

 printf "\n};\n\nconst unsigned int %s_len = %u;\n", $table_name, $total_len;

-@st = stat STDIN;

-

-printf "\nconst int %s_mtime = %d;\n", $table_name, $st[9];

-

 exit 0;

diff --git a/libinstaller/syslinux.h b/libinstaller/syslinux.h

index 710d30e..963cafe 100644

--- a/libinstaller/syslinux.h

+++ b/libinstaller/syslinux.h

@@ -20,11 +20,9 @@

 /* The standard boot sector and ldlinux image */

 extern unsigned char syslinux_bootsect[];

 extern const unsigned int syslinux_bootsect_len;

-extern const int syslinux_bootsect_mtime;

 extern unsigned char syslinux_ldlinux[];

 extern const unsigned int syslinux_ldlinux_len;

-extern const int syslinux_ldlinux_mtime;

 #define boot_sector	syslinux_bootsect

 #define boot_sector_len syslinux_bootsect_len

@@ -33,7 +31,6 @@ extern const int syslinux_ldlinux_mtime;

 extern unsigned char syslinux_mbr[];

 extern const unsigned int syslinux_mbr_len;

-extern const int syslinux_mbr_mtime;

 /* Sector size assumptions... */

 #define SECTOR_SHIFT	9

diff --git a/now.pl b/now.pl

old mode 100644

new mode 100755

index a3b5a79..60c4fe0

--- a/now.pl

+++ b/now.pl

@@ -1,21 +1,22 @@

-#!/usr/bin/perl

-#

-# Print the time (possibly the mtime of a file) as a hexadecimal integer

-# If more than one file, print the mtime of the *newest* file.

-#

-

-undef $now;

-

-foreach $file ( @ARGV ) {

-    ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,

-     $ctime,$blksize,$blocks) = stat($file);

-    if ( !defined($now) || $now < $mtime ) {

-	$now = $mtime;

-    }

-}

+#! /usr/bin/perl

+

+# Use checksum over all sources and source file names to create some unique id.

+

+use Digest::SHA;

+

+use strict;

-if ( !defined($now) ) {

-    $now = time;

+my $digest = Digest::SHA->new(256);

+

+# print STDERR "now.pl: ", join(" ", @ARGV) , "\n";

+

+for (sort @ARGV) {

+  $digest->add($_);

+  $digest->addfile($_);

 }

-printf "0x%08x\n", $now;

+my $val = substr($digest->hexdigest, 0, 8);

+

+# printf STDERR "now.pl: = 0x$val\n";

+

+print "0x$val\n";