diff -Nru busybox-1.4.2/include/applets.h src/include/applets.h
--- busybox-1.4.2/include/applets.h	2007-03-18 17:59:34.000000000 +0100
+++ src/include/applets.h	2007-04-23 18:00:13.000000000 +0200
@@ -303,6 +303,7 @@
 USE_UMOUNT(APPLET(umount, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_UNAME(APPLET(uname, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_UNCOMPRESS(APPLET(uncompress, _BB_DIR_BIN, _BB_SUID_NEVER))
+USE_UNHEXDUMP(APPLET(unhexdump, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_UNIQ(APPLET(uniq, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
 USE_UNIX2DOS(APPLET_ODDNAME(unix2dos, dos2unix, _BB_DIR_USR_BIN, _BB_SUID_NEVER, unix2dos))
 USE_UNLZMA(APPLET(unlzma, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
diff -Nru busybox-1.4.2/include/usage.h src/include/usage.h
--- busybox-1.4.2/include/usage.h	2007-03-18 17:59:34.000000000 +0100
+++ src/include/usage.h	2007-04-23 17:58:44.000000000 +0200
@@ -1229,6 +1229,9 @@
        "	-v		Display all input data\n" \
        "	-x		Two-byte hexadecimal display"
 
+#define unhexdump_trivial_usage \
+	"unhexdump < in > out"
+
 #define hostid_trivial_usage \
        ""
 #define hostid_full_usage \
diff -Nru busybox-1.4.2/util-linux/Config.in src/util-linux/Config.in
--- busybox-1.4.2/util-linux/Config.in	2007-03-18 17:59:37.000000000 +0100
+++ src/util-linux/Config.in	2007-04-23 17:57:40.000000000 +0200
@@ -210,6 +210,14 @@
 	  The hexdump utility is used to display binary data in a readable
 	  way that is comparable to the output from most hex editors.
 
+config UNHEXDUMP
+	bool "unhexdump"
+	default n
+	help
+
+	  The  unhexdump  utility  is  used  to convert  a  stream  of
+	  hexadecimal chars to in a raw binary form.
+
 config HWCLOCK
 	bool "hwclock"
 	default n
diff -Nru busybox-1.4.2/util-linux/Kbuild src/util-linux/Kbuild
--- busybox-1.4.2/util-linux/Kbuild	2007-03-18 17:59:37.000000000 +0100
+++ src/util-linux/Kbuild	2007-04-23 17:56:04.000000000 +0200
@@ -30,3 +30,4 @@
 lib-$(CONFIG_SWAPONOFF)		+=swaponoff.o
 lib-$(CONFIG_SWITCH_ROOT)	+=switch_root.o
 lib-$(CONFIG_UMOUNT)		+=umount.o
+lib-$(CONFIG_UNHEXDUMP)		+=unhexdump.o
diff -Nru busybox-1.4.2/util-linux/unhexdump.c src/util-linux/unhexdump.c
--- busybox-1.4.2/util-linux/unhexdump.c	1970-01-01 01:00:00.000000000 +0100
+++ src/util-linux/unhexdump.c	2007-04-23 18:48:46.000000000 +0200
@@ -0,0 +1,82 @@
+/*
+ * main.c for unhexdump
+ * Created by <nschichan@freebox.fr> on Mon Apr 23 15:04:43 2007
+ * Freebox SA
+ */
+
+#include <unistd.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int to_hex(int c)
+{
+	const char *pos;
+	const char *HEX_chars = "0123456789ABCDEF";
+	const char *hex_chars = "0123456789abcdef";
+
+	pos = strchr(hex_chars, c);
+	if (pos == NULL) {
+		pos = strchr(HEX_chars, c);
+		if (pos == NULL)
+			return -1;
+		else
+			return pos - HEX_chars;
+	} else
+		return pos - hex_chars;
+}
+
+/*
+ * convert a stream of hexadecimal on chars on stdin to raw binary
+ * data. output is done on stdout.
+ *
+ * I was unable to find any ready to use busybox applet to do so, but
+ * if you do, I'll be glad to revert this code.
+ */
+int
+unhexdump_main(int argc, char **argv)
+{
+	char buf[4096];
+
+	while (1) {
+		int i;
+		int len;
+
+		len = fread(buf, 1, sizeof (buf), stdin);
+		if (len < 0) {
+			perror("stdin");
+			return 1;
+		}
+
+		if (len == 0)
+			break;
+		for (i = 0; i < len; i += 2) {
+			int c;
+			unsigned char val;
+
+			if (buf[i] == '\n') {
+				fflush(NULL);
+				exit(0);
+			}
+
+			c = to_hex(buf[i]);
+			if (c < 0) {
+				fprintf(stderr, "bad hex: %c\n", c);
+				exit(1);
+			}
+			val = c << 4;
+			c = to_hex(buf[i + 1]);
+			if (c < 0) {
+				fprintf(stderr, "bad hex: %c\n", c);
+				exit(1);
+			}
+			val |= c;
+
+			fwrite(&val, 1, 1, stdout);
+		}
+	}
+
+	(void)argc;
+	(void)argv;
+	return 0;
+}