diff -urN busybox-1.7.0/archival/bbunzip.c busybox-1.7.0-targz_nommu/archival/bbunzip.c
--- busybox-1.7.0/archival/bbunzip.c	2007-08-24 11:49:45.000000000 +0100
+++ busybox-1.7.0-targz_nommu/archival/bbunzip.c	2007-09-06 17:42:02.000000000 +0100
@@ -298,7 +298,7 @@
 int unlzma_main(int argc, char **argv);
 int unlzma_main(int argc, char **argv)
 {
-	getopt32(argv, "c");
+	getopt32(argv, "cf");
 	argv += optind;
 	/* lzmacat? */
 	if (applet_name[4] == 'c')
diff -urN busybox-1.7.0/archival/libunarchive/Kbuild busybox-1.7.0-targz_nommu/archival/libunarchive/Kbuild
--- busybox-1.7.0/archival/libunarchive/Kbuild	2007-08-24 11:49:45.000000000 +0100
+++ busybox-1.7.0-targz_nommu/archival/libunarchive/Kbuild	2007-09-06 17:42:02.000000000 +0100
@@ -35,36 +35,34 @@
 	get_header_tar.o \
 	filter_accept_list_reassign.o
 
-# open_transformer uses fork(). Compile it only if absolutely necessary
 lib-$(CONFIG_RPM)                       += open_transformer.o
-lib-$(CONFIG_FEATURE_TAR_BZIP2)	        += open_transformer.o
-lib-$(CONFIG_FEATURE_TAR_LZMA)	        += open_transformer.o
-lib-$(CONFIG_FEATURE_TAR_GZIP)		+= open_transformer.o
-lib-$(CONFIG_FEATURE_TAR_COMPRESS)	+= open_transformer.o
-lib-$(CONFIG_FEATURE_DEB_TAR_GZ)	+= open_transformer.o
-lib-$(CONFIG_FEATURE_DEB_TAR_BZ2)	+= open_transformer.o
-lib-$(CONFIG_FEATURE_DEB_TAR_LZMA)	+= open_transformer.o
-
-lib-$(CONFIG_AR)			+= get_header_ar.o unpack_ar_archive.o
-lib-$(CONFIG_BUNZIP2)			+= decompress_bunzip2.o
-lib-$(CONFIG_UNLZMA)			+= decompress_unlzma.o
-lib-$(CONFIG_CPIO)			+= get_header_cpio.o
-lib-$(CONFIG_DPKG)			+= $(DPKG_FILES)
-lib-$(CONFIG_DPKG_DEB)			+= $(DPKG_FILES)
-lib-$(CONFIG_FEATURE_DEB_TAR_GZ)	+= $(GUNZIP_FILES) get_header_tar_gz.o
-lib-$(CONFIG_FEATURE_DEB_TAR_BZ2)	+= decompress_bunzip2.o get_header_tar_bz2.o
-lib-$(CONFIG_FEATURE_DEB_TAR_LZMA)	+= decompress_unlzma.o get_header_tar_lzma.o
-lib-$(CONFIG_GUNZIP)			+= $(GUNZIP_FILES)
-lib-$(CONFIG_FEATURE_GUNZIP_UNCOMPRESS)	+= decompress_uncompress.o
-lib-$(CONFIG_RPM2CPIO)			+= $(GUNZIP_FILES) get_header_cpio.o
-lib-$(CONFIG_RPM)			+= $(GUNZIP_FILES) get_header_cpio.o
-lib-$(CONFIG_FEATURE_RPM_BZ2)		+= decompress_bunzip2.o
-lib-$(CONFIG_TAR)			+= get_header_tar.o
-lib-$(CONFIG_FEATURE_TAR_BZIP2)		+= decompress_bunzip2.o get_header_tar_bz2.o
-lib-$(CONFIG_FEATURE_TAR_LZMA)		+= decompress_unlzma.o get_header_tar_lzma.o
-lib-$(CONFIG_FEATURE_TAR_GZIP)		+= $(GUNZIP_FILES) get_header_tar_gz.o
-lib-$(CONFIG_FEATURE_TAR_COMPRESS)	+= decompress_uncompress.o
-lib-$(CONFIG_UNCOMPRESS)		+= decompress_uncompress.o
-lib-$(CONFIG_UNZIP)			+= $(GUNZIP_FILES)
-lib-$(CONFIG_FEATURE_COMPRESS_USAGE)	+= decompress_bunzip2.o
+lib-$(CONFIG_FEATURE_TAR_BZIP2)         += open_transformer.o
+lib-$(CONFIG_FEATURE_TAR_LZMA)          += open_transformer.o
+lib-$(CONFIG_FEATURE_TAR_GZIP)          += open_transformer.o
+lib-$(CONFIG_FEATURE_TAR_COMPRESS)      += open_transformer.o
+lib-$(CONFIG_FEATURE_DEB_TAR_GZ)        += open_transformer.o
+lib-$(CONFIG_FEATURE_DEB_TAR_BZ2)       += open_transformer.o
+lib-$(CONFIG_FEATURE_DEB_TAR_LZMA)      += open_transformer.o
 
+lib-$(CONFIG_AR)                        += get_header_ar.o unpack_ar_archive.o
+lib-$(CONFIG_BUNZIP2)                   += decompress_bunzip2.o
+lib-$(CONFIG_UNLZMA)                    += decompress_unlzma.o
+lib-$(CONFIG_CPIO)                      += get_header_cpio.o
+lib-$(CONFIG_DPKG)                      += $(DPKG_FILES)
+lib-$(CONFIG_DPKG_DEB)                  += $(DPKG_FILES)
+lib-$(CONFIG_FEATURE_DEB_TAR_GZ)        += $(GUNZIP_FILES) get_header_tar_gz.o
+lib-$(CONFIG_FEATURE_DEB_TAR_BZ2)       += decompress_bunzip2.o get_header_tar_bz2.o
+lib-$(CONFIG_FEATURE_DEB_TAR_LZMA)      += decompress_unlzma.o get_header_tar_lzma.o
+lib-$(CONFIG_GUNZIP)                    += $(GUNZIP_FILES)
+lib-$(CONFIG_FEATURE_GUNZIP_UNCOMPRESS) += decompress_uncompress.o
+lib-$(CONFIG_RPM2CPIO)                  += $(GUNZIP_FILES) get_header_cpio.o
+lib-$(CONFIG_RPM)                       += $(GUNZIP_FILES) get_header_cpio.o
+lib-$(CONFIG_FEATURE_RPM_BZ2)           += decompress_bunzip2.o
+lib-$(CONFIG_TAR)                       += get_header_tar.o
+lib-$(CONFIG_FEATURE_TAR_BZIP2)         += decompress_bunzip2.o get_header_tar_bz2.o
+lib-$(CONFIG_FEATURE_TAR_LZMA)          += decompress_unlzma.o get_header_tar_lzma.o
+lib-$(CONFIG_FEATURE_TAR_GZIP)          += $(GUNZIP_FILES) get_header_tar_gz.o
+lib-$(CONFIG_FEATURE_TAR_COMPRESS)      += decompress_uncompress.o
+lib-$(CONFIG_UNCOMPRESS)                += decompress_uncompress.o
+lib-$(CONFIG_UNZIP)                     += $(GUNZIP_FILES)
+lib-$(CONFIG_FEATURE_COMPRESS_USAGE)    += decompress_bunzip2.o
diff -urN busybox-1.7.0/archival/libunarchive/get_header_tar_bz2.c busybox-1.7.0-targz_nommu/archival/libunarchive/get_header_tar_bz2.c
--- busybox-1.7.0/archival/libunarchive/get_header_tar_bz2.c	2007-08-24 11:49:45.000000000 +0100
+++ busybox-1.7.0-targz_nommu/archival/libunarchive/get_header_tar_bz2.c	2007-09-06 17:42:02.000000000 +0100
@@ -11,7 +11,7 @@
 	/* Can't lseek over pipes */
 	archive_handle->seek = seek_by_read;
 
-	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_bz2_stream);
+	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_bz2_stream, "bunzip2", "bunzip2", "-cf", "-", NULL);
 	archive_handle->offset = 0;
 	while (get_header_tar(archive_handle) == EXIT_SUCCESS) /**/;
 
diff -urN busybox-1.7.0/archival/libunarchive/get_header_tar_gz.c busybox-1.7.0-targz_nommu/archival/libunarchive/get_header_tar_gz.c
--- busybox-1.7.0/archival/libunarchive/get_header_tar_gz.c	2007-08-24 11:49:45.000000000 +0100
+++ busybox-1.7.0-targz_nommu/archival/libunarchive/get_header_tar_gz.c	2007-09-06 17:42:02.000000000 +0100
@@ -8,19 +8,26 @@
 
 char get_header_tar_gz(archive_handle_t *archive_handle)
 {
+#if BB_MMU
 	unsigned char magic[2];
+#endif
 
 	/* Can't lseek over pipes */
 	archive_handle->seek = seek_by_read;
 
+	/* Check gzip magic only if open_transformer will invoke unpack_gz_stream (MMU case).
+	 * Otherwise, it will invoke an external helper "gunzip -cf" (NOMMU case) which will
+	 * need the header. */
+#if BB_MMU
 	xread(archive_handle->src_fd, &magic, 2);
 	if ((magic[0] != 0x1f) || (magic[1] != 0x8b)) {
 		bb_error_msg_and_die("invalid gzip magic");
 	}
 
 	check_header_gzip_or_die(archive_handle->src_fd);
+#endif
 
-	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_gz_stream);
+	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_gz_stream, "gunzip", "gunzip", "-cf", "-", NULL);
 	archive_handle->offset = 0;
 	while (get_header_tar(archive_handle) == EXIT_SUCCESS) /**/;
 
diff -urN busybox-1.7.0/archival/libunarchive/get_header_tar_lzma.c busybox-1.7.0-targz_nommu/archival/libunarchive/get_header_tar_lzma.c
--- busybox-1.7.0/archival/libunarchive/get_header_tar_lzma.c	2007-08-24 11:49:45.000000000 +0100
+++ busybox-1.7.0-targz_nommu/archival/libunarchive/get_header_tar_lzma.c	2007-09-06 17:42:02.000000000 +0100
@@ -14,7 +14,7 @@
 	/* Can't lseek over pipes */
 	archive_handle->seek = seek_by_read;
 
-	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_lzma_stream);
+	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_lzma_stream, "unlzma", "unlzma", "-cf", "-", NULL);
 	archive_handle->offset = 0;
 	while (get_header_tar(archive_handle) == EXIT_SUCCESS) /**/;
 
diff -urN busybox-1.7.0/archival/libunarchive/open_transformer.c busybox-1.7.0-targz_nommu/archival/libunarchive/open_transformer.c
--- busybox-1.7.0/archival/libunarchive/open_transformer.c	2007-08-24 11:49:45.000000000 +0100
+++ busybox-1.7.0-targz_nommu/archival/libunarchive/open_transformer.c	2007-09-05 12:28:55.000000000 +0100
@@ -7,27 +7,48 @@
 #include "unarchive.h"
 
 /* transformer(), more than meets the eye */
+/*
+ * On MMU machine, the transform_prog and ... are stripped
+ * by a macro in include/unarchive.h. On NOMMU, transformer is stripped.
+ */
 int open_transformer(int src_fd,
-	USE_DESKTOP(long long) int (*transformer)(int src_fd, int dst_fd))
+	USE_DESKTOP(long long) int (*transformer)(int src_fd, int dst_fd),
+	const char *transform_prog, ...)
 {
 	int fd_pipe[2];
 	int pid;
 
 	xpipe(fd_pipe);
 
+#if BB_MMU
 	pid = fork();
-	if (pid == -1) {
+#else
+	pid = vfork();
+#endif
+	if (pid == -1)
 		bb_perror_msg_and_die("fork failed");
-	}
 
 	if (pid == 0) {
+#if !BB_MMU
+		va_list ap;
+#endif
 		/* child process */
 		close(fd_pipe[0]); /* We don't wan't to read from the parent */
 		// FIXME: error check?
+#if BB_MMU
 		transformer(src_fd, fd_pipe[1]);
-		close(fd_pipe[1]); /* Send EOF */
-		close(src_fd);
+		if (ENABLE_FEATURE_CLEAN_UP) {
+			close(fd_pipe[1]); /* Send EOF */
+			close(src_fd);
+		}
 		exit(0);
+#else
+		xmove_fd(src_fd, 0);
+		xmove_fd(fd_pipe[1], 1);
+		va_start(ap, transform_prog);
+		BB_EXECVP(transform_prog, ap);
+		bb_perror_and_die("exec failed");
+#endif
 		/* notreached */
 	}
 
diff -urN busybox-1.7.0/archival/rpm.c busybox-1.7.0-targz_nommu/archival/rpm.c
--- busybox-1.7.0/archival/rpm.c	2007-08-24 11:49:45.000000000 +0100
+++ busybox-1.7.0-targz_nommu/archival/rpm.c	2007-09-06 17:42:02.000000000 +0100
@@ -187,9 +187,15 @@
 
 static void extract_cpio_gz(int fd)
 {
-	USE_DESKTOP(long long) int (*xformer)(int src_fd, int dst_fd);
 	archive_handle_t *archive_handle;
 	unsigned char magic[2];
+#if BB_MMU
+	USE_DESKTOP(long long) int (*xformer)(int src_fd, int dst_fd);
+	enum { xformer_prog = 0 };
+#else
+	enum { xformer = 0 };
+	const char *xformer_prog;
+#endif
 
 	/* Initialize */
 	archive_handle = init_handle();
@@ -202,11 +208,19 @@
 	archive_handle->offset = 0;
 
 	xread(archive_handle->src_fd, &magic, 2);
+#if BB_MMU
 	xformer = unpack_gz_stream;
+#else
+	xformer_prog = "gunzip";
+#endif
 	if ((magic[0] != 0x1f) || (magic[1] != 0x8b)) {
 		if (ENABLE_FEATURE_RPM_BZ2
 		 && (magic[0] == 0x42) && (magic[1] == 0x5a)) {
+#if BB_MMU
 			xformer = unpack_bz2_stream;
+#else
+			xformer_prog = "bunzip2";
+#endif
 	/* We can do better, need modifying unpack_bz2_stream to not require
 	 * first 2 bytes. Not very hard to do... I mean, TODO :) */
 			xlseek(archive_handle->src_fd, -2, SEEK_CUR);
@@ -214,11 +228,17 @@
 			bb_error_msg_and_die("no gzip"
 				USE_FEATURE_RPM_BZ2("/bzip")
 				" magic");
-	} else
+	} else {
 		check_header_gzip_or_die(archive_handle->src_fd);
+#if !BB_MMU
+		/* NOMMU version of open_transformer execs an external unzipper that should
+		 * have the file position at the start of the file */
+		xlseek(archive_handle->src_fd, 0, SEEK_SET);
+#endif
+	}
 
 	xchdir("/"); /* Install RPM's to root */
-	archive_handle->src_fd = open_transformer(archive_handle->src_fd, xformer);
+	archive_handle->src_fd = open_transformer(archive_handle->src_fd, xformer, xformer_prog, xformer_prog, "-cf", "-", NULL);
 	archive_handle->offset = 0;
 	while (get_header_cpio(archive_handle) == EXIT_SUCCESS)
 		continue;
diff -urN busybox-1.7.0/archival/tar.c busybox-1.7.0-targz_nommu/archival/tar.c
--- busybox-1.7.0/archival/tar.c	2007-08-24 11:49:45.000000000 +0100
+++ busybox-1.7.0-targz_nommu/archival/tar.c	2007-09-06 17:42:02.000000000 +0100
@@ -648,7 +648,7 @@
 		bb_error_msg_and_die("invalid magic");
 	}
 
-	archive_handle->src_fd = open_transformer(archive_handle->src_fd, uncompress);
+	archive_handle->src_fd = open_transformer(archive_handle->src_fd, uncompress, "uncompress", "uncompress", "-cf", "-", NULL);
 	archive_handle->offset = 0;
 	while (get_header_tar(archive_handle) == EXIT_SUCCESS)
 		/* nothing */;
diff -urN busybox-1.7.0/include/unarchive.h busybox-1.7.0-targz_nommu/include/unarchive.h
--- busybox-1.7.0/include/unarchive.h	2007-08-24 11:49:55.000000000 +0100
+++ busybox-1.7.0-targz_nommu/include/unarchive.h	2007-09-06 17:42:02.000000000 +0100
@@ -115,7 +115,13 @@
 extern USE_DESKTOP(long long) int unpack_gz_stream(int src_fd, int dst_fd);
 extern USE_DESKTOP(long long) int unpack_lzma_stream(int src_fd, int dst_fd);
 
+#if BB_MMU
 extern int open_transformer(int src_fd,
 	USE_DESKTOP(long long) int (*transformer)(int src_fd, int dst_fd));
+#define open_transformer(src_fd, transformer, transform_prog, ...) open_transformer(src_fd, transformer)
+#else
+extern int open_transformer(int src_fd, const char *transform_prog, ...);
+#define open_transformer(src_fd, transformer, transform_prog, ...) open_transformer(src_fd, transform_prog, __VA_ARGS__)
+#endif
 
 #endif