diff --git a/debian/changelog b/debian/changelog
index 10eccbd..2dccf6a 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -5,6 +5,14 @@
       - lzma_easy_buffer_encode() and lzma_stream_buffer_encode()
         avoid writing Blocks with empty compressed data that xz and
         liblzma versions before 5.0.2 cannot read.
+      - The LZMA2 decoder skips Blocks with empty compressed data
+        instead of rejecting them.
+      - Validates encoder arguments better.  It is harder to segfault
+        or create a corrupt XZ file instead of receiving an error
+        when calling these functions:
+        - lzma_stream_buffer_encode() and lzma_block_buffer_encode()
+          reject unsupported integrity checks;
+        - lzma_block_encoder() checks for block == NULL.
       - Plugs a memory leak in lzma_stream_encoder().
       - lzma_index_init() returns NULL instead of segfaulting on
         allocation failure.
@@ -13,6 +21,9 @@
       reading and free()ing pointers from past the end of an on-stack
       array when one of the listed files has an unmeaningful Block
       header size.
+    * xzegrep and xzfgrep perform extended regex and fixed-string
+      matches, respectively.  (The previous behavior was to always
+      use basic regexes.)
     * The exit status from “xzdiff foo.xz bar.xz” reflects whether
       files differ.  Thanks to Peter Pallinger.  Closes: #635501.
     * xzgrep does not fail just because the decompressor has died
@@ -24,8 +35,8 @@
       extra 'N'.
   * debian/rules: "chmod +x tests/test_scripts.sh" for new xzdiff
     tests.
-  * debian/symbols: Bump minimal versions for lzma_easy_buffer_encode
-    and lzma_stream_buffer_encode.
+  * debian/symbols: Bump the minimal versions for LZMA2 encoder
+    functions that reject more bad arguments and skip empty blocks.
   * liblzma-dev: Install an appropriate library for static linking
     instead of the decompression-only version used to build xzdec.
     Thanks to Anton Tolchanov.  Closes: #673001.
diff --git a/debian/patches/decode-empty-blocks b/debian/patches/decode-empty-blocks
new file mode 100644
index 0000000..89fea1b
--- /dev/null
+++ b/debian/patches/decode-empty-blocks
@@ -0,0 +1,41 @@
+From: Lasse Collin <lasse.collin@tukaani.org>
+Date: Thu, 31 Mar 2011 11:54:48 +0300
+Subject: liblzma: Fix decoding of LZMA2 streams having no uncompressed data.
+
+The decoder considered empty LZMA2 streams to be corrupt.
+This shouldn't matter much with .xz files, because no encoder
+creates empty LZMA2 streams in .xz. This bug is more likely
+to cause problems in applications that use raw LZMA2 streams.
+---
+ src/liblzma/lzma/lzma2_decoder.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/src/liblzma/lzma/lzma2_decoder.c b/src/liblzma/lzma/lzma2_decoder.c
+index f38879ce..3e42575d 100644
+--- a/src/liblzma/lzma/lzma2_decoder.c
++++ b/src/liblzma/lzma/lzma2_decoder.c
+@@ -67,6 +67,10 @@ lzma2_decode(lzma_coder *restrict coder, lzma_dict *restrict dict,
+ 		const uint32_t control = in[*in_pos];
+ 		++*in_pos;
+ 
++		// End marker
++		if (control == 0x00)
++			return LZMA_STREAM_END;
++
+ 		if (control >= 0xE0 || control == 1) {
+ 			// Dictionary reset implies that next LZMA chunk has
+ 			// to set new properties.
+@@ -104,10 +108,6 @@ lzma2_decode(lzma_coder *restrict coder, lzma_dict *restrict dict,
+ 							&coder->options);
+ 			}
+ 		} else {
+-			// End marker
+-			if (control == 0x00)
+-				return LZMA_STREAM_END;
+-
+ 			// Invalid control values
+ 			if (control > 2)
+ 				return LZMA_DATA_ERROR;
+-- 
+1.7.11.rc3
+
diff --git a/debian/patches/decode-empty-blocks-test b/debian/patches/decode-empty-blocks-test
new file mode 100644
index 0000000..e97bb28
--- /dev/null
+++ b/debian/patches/decode-empty-blocks-test
@@ -0,0 +1,28 @@
+From: Lasse Collin <lasse.collin@tukaani.org>
+Date: Thu, 31 Mar 2011 12:22:55 +0300
+Subject: Tests: Add a new file to test empty LZMA2 streams.
+
+---
+ tests/files/README            |   4 ++++
+ tests/files/good-1-lzma2-5.xz | Bin 0 -> 52 bytes
+ 2 files changed, 4 insertions(+)
+ create mode 100644 tests/files/good-1-lzma2-5.xz
+
+diff --git a/tests/files/README b/tests/files/README
+index 108ce8fb..53950edb 100644
+--- a/tests/files/README
++++ b/tests/files/README
+@@ -87,6 +87,10 @@
+     uncompressed with dictionary reset, and third is LZMA with new
+     properties but without dictionary reset.
+ 
++    good-1-lzma2-5.xz has an empty LZMA2 stream with only the end of
++    payload marker. XZ Utils 5.0.1 and older incorrectly see this file
++    as corrupt.
++
+     good-1-3delta-lzma2.xz has three Delta filters and LZMA2.
+ 
+ 
+-- 
+1.7.11.rc3
+
diff --git a/debian/patches/encoder-api-checks b/debian/patches/encoder-api-checks
new file mode 100644
index 0000000..0ff5341
--- /dev/null
+++ b/debian/patches/encoder-api-checks
@@ -0,0 +1,91 @@
+From: Lasse Collin <lasse.collin@tukaani.org>
+Date: Mon, 11 Apr 2011 13:21:28 +0300
+Subject: liblzma: Validate encoder arguments better.
+
+The biggest problem was that the integrity check type
+wasn't validated, and e.g. lzma_easy_buffer_encode()
+would create a corrupt .xz Stream if given an unsupported
+Check ID. Luckily applications don't usually try to use
+an unsupport Check ID, so this bug is unlikely to cause
+many real-world problems.
+---
+ src/liblzma/common/block_buffer_encoder.c  | 18 ++++++++++++------
+ src/liblzma/common/block_encoder.c         |  5 +++++
+ src/liblzma/common/stream_buffer_encoder.c |  3 +++
+ 3 files changed, 20 insertions(+), 6 deletions(-)
+
+diff --git a/src/liblzma/common/block_buffer_encoder.c b/src/liblzma/common/block_buffer_encoder.c
+index a8f71c21..519c6a68 100644
+--- a/src/liblzma/common/block_buffer_encoder.c
++++ b/src/liblzma/common/block_buffer_encoder.c
+@@ -226,16 +226,23 @@ lzma_block_buffer_encode(lzma_block *block, lzma_allocator *allocator,
+ 		const uint8_t *in, size_t in_size,
+ 		uint8_t *out, size_t *out_pos, size_t out_size)
+ {
+-	// Sanity checks
+-	if (block == NULL || block->filters == NULL
+-			|| (in == NULL && in_size != 0) || out == NULL
++	// Validate the arguments.
++	if (block == NULL || (in == NULL && in_size != 0) || out == NULL
+ 			|| out_pos == NULL || *out_pos > out_size)
+ 		return LZMA_PROG_ERROR;
+ 
+-	// Check the version field.
++	// The contents of the structure may depend on the version so
++	// check the version before validating the contents of *block.
+ 	if (block->version != 0)
+ 		return LZMA_OPTIONS_ERROR;
+ 
++	if ((unsigned int)(block->check) > LZMA_CHECK_ID_MAX
++			|| block->filters == NULL)
++		return LZMA_PROG_ERROR;
++
++	if (!lzma_check_is_supported(block->check))
++		return LZMA_UNSUPPORTED_CHECK;
++
+ 	// Size of a Block has to be a multiple of four, so limit the size
+ 	// here already. This way we don't need to check it again when adding
+ 	// Block Padding.
+@@ -243,8 +250,7 @@ lzma_block_buffer_encode(lzma_block *block, lzma_allocator *allocator,
+ 
+ 	// Get the size of the Check field.
+ 	const size_t check_size = lzma_check_size(block->check);
+-	if (check_size == UINT32_MAX)
+-		return LZMA_PROG_ERROR;
++	assert(check_size != UINT32_MAX);
+ 
+ 	// Reserve space for the Check field.
+ 	if (out_size - *out_pos <= check_size)
+diff --git a/src/liblzma/common/block_encoder.c b/src/liblzma/common/block_encoder.c
+index ca515235..b34c5013 100644
+--- a/src/liblzma/common/block_encoder.c
++++ b/src/liblzma/common/block_encoder.c
+@@ -161,6 +161,11 @@ lzma_block_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+ {
+ 	lzma_next_coder_init(&lzma_block_encoder_init, next, allocator);
+ 
++	if (block == NULL)
++		return LZMA_PROG_ERROR;
++
++	// The contents of the structure may depend on the version so
++	// check the version first.
+ 	if (block->version != 0)
+ 		return LZMA_OPTIONS_ERROR;
+ 
+diff --git a/src/liblzma/common/stream_buffer_encoder.c b/src/liblzma/common/stream_buffer_encoder.c
+index 0542c30a..2450ee2e 100644
+--- a/src/liblzma/common/stream_buffer_encoder.c
++++ b/src/liblzma/common/stream_buffer_encoder.c
+@@ -51,6 +51,9 @@ lzma_stream_buffer_encode(lzma_filter *filters, lzma_check check,
+ 			|| out_pos_ptr == NULL || *out_pos_ptr > out_size)
+ 		return LZMA_PROG_ERROR;
+ 
++	if (!lzma_check_is_supported(check))
++		return LZMA_UNSUPPORTED_CHECK;
++
+ 	// Note for the paranoids: Index encoder prevents the Stream from
+ 	// getting too big and still being accepted with LZMA_OK, and Block
+ 	// encoder catches if the input is too big. So we don't need to
+-- 
+1.7.11.rc3
+
diff --git a/debian/patches/series b/debian/patches/series
index 958e893..fa7f036 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -2,8 +2,12 @@
 abi-chunk-size-func
 abi-debian-soname
 cs-sparse-file
+encoder-api-checks
+decode-empty-blocks
+decode-empty-blocks-test
 stream_encoder-init-leak
 encoder-skip-empty-blocks
+xzgrep-argv0-parsing
 index_init-NULL-dereference
 xz-lvv-invalid-free
 xz-lvv-invalid-free-test
diff --git a/debian/patches/xzgrep-argv0-parsing b/debian/patches/xzgrep-argv0-parsing
new file mode 100644
index 0000000..c3e2a58
--- /dev/null
+++ b/debian/patches/xzgrep-argv0-parsing
@@ -0,0 +1,36 @@
+From: Martin Väth <vaeth@mathematik.uni-wuerzburg.de>
+Date: Fri, 15 Apr 2011 04:54:49 -0400
+Subject: xzgrep: fix typo in $0 parsing
+
+Reported-by: Diego Elio Pettenò <flameeyes@gentoo.org>
+Signed-off-by: Martin Väth <vaeth@mathematik.uni-wuerzburg.de>
+Signed-off-by: Mike Frysinger <vapier@gentoo.org>
+---
+ src/scripts/xzgrep.in | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/src/scripts/xzgrep.in b/src/scripts/xzgrep.in
+index cbc6b238..dd945137 100644
+--- a/src/scripts/xzgrep.in
++++ b/src/scripts/xzgrep.in
+@@ -27,7 +27,7 @@
+ xz='@xz@ --format=auto'
+ unset GZIP BZIP BZIP2
+ 
+-case ${0##/*} in
++case ${0##*/} in
+   *egrep*) prog=xzegrep; grep=${GREP:-egrep};;
+   *fgrep*) prog=xzfgrep; grep=${GREP:-fgrep};;
+   *)       prog=xzgrep; grep=${GREP:-grep};;
+@@ -35,7 +35,7 @@ esac
+ 
+ version="$prog (@PACKAGE_NAME@) @VERSION@"
+ 
+-usage="Usage: ${0##/*} [OPTION]... [-e] PATTERN [FILE]...
++usage="Usage: ${0##*/} [OPTION]... [-e] PATTERN [FILE]...
+ Look for instances of PATTERN in the input FILEs, using their
+ uncompressed contents if they are compressed.
+ 
+-- 
+1.7.11.rc3
+
diff --git a/debian/source/include-binaries b/debian/source/include-binaries
index d4f7e04..bc7b083 100644
--- a/debian/source/include-binaries
+++ b/debian/source/include-binaries
@@ -1 +1,2 @@
 tests/files/bad-1-block_header-6.xz
+tests/files/good-1-lzma2-5.xz
diff --git a/debian/symbols b/debian/symbols
index 82322ba..1a7d6ea 100644
--- a/debian/symbols
+++ b/debian/symbols
@@ -5,10 +5,10 @@
  lzma_auto_decoder@Base 4.999.9beta
  lzma_block_buffer_bound@Base 4.999.9beta
  lzma_block_buffer_decode@Base 4.999.9beta
- lzma_block_buffer_encode@Base 4.999.9beta
+ lzma_block_buffer_encode@Base 5.0.0-2.1~
  lzma_block_compressed_size@Base 4.999.9beta+20100602
  lzma_block_decoder@Base 4.999.9beta
- lzma_block_encoder@Base 4.999.9beta
+ lzma_block_encoder@Base 5.0.0-2.1~
  lzma_block_header_decode@Base 4.999.9beta
  lzma_block_header_encode@Base 4.999.9beta
  lzma_block_header_size@Base 4.999.9beta
diff --git a/src/liblzma/common/block_buffer_encoder.c b/src/liblzma/common/block_buffer_encoder.c
index a8f71c2..519c6a6 100644
--- a/src/liblzma/common/block_buffer_encoder.c
+++ b/src/liblzma/common/block_buffer_encoder.c
@@ -226,16 +226,23 @@
 		const uint8_t *in, size_t in_size,
 		uint8_t *out, size_t *out_pos, size_t out_size)
 {
-	// Sanity checks
-	if (block == NULL || block->filters == NULL
-			|| (in == NULL && in_size != 0) || out == NULL
+	// Validate the arguments.
+	if (block == NULL || (in == NULL && in_size != 0) || out == NULL
 			|| out_pos == NULL || *out_pos > out_size)
 		return LZMA_PROG_ERROR;
 
-	// Check the version field.
+	// The contents of the structure may depend on the version so
+	// check the version before validating the contents of *block.
 	if (block->version != 0)
 		return LZMA_OPTIONS_ERROR;
 
+	if ((unsigned int)(block->check) > LZMA_CHECK_ID_MAX
+			|| block->filters == NULL)
+		return LZMA_PROG_ERROR;
+
+	if (!lzma_check_is_supported(block->check))
+		return LZMA_UNSUPPORTED_CHECK;
+
 	// Size of a Block has to be a multiple of four, so limit the size
 	// here already. This way we don't need to check it again when adding
 	// Block Padding.
@@ -243,8 +250,7 @@
 
 	// Get the size of the Check field.
 	const size_t check_size = lzma_check_size(block->check);
-	if (check_size == UINT32_MAX)
-		return LZMA_PROG_ERROR;
+	assert(check_size != UINT32_MAX);
 
 	// Reserve space for the Check field.
 	if (out_size - *out_pos <= check_size)
diff --git a/src/liblzma/common/block_encoder.c b/src/liblzma/common/block_encoder.c
index ca51523..b34c501 100644
--- a/src/liblzma/common/block_encoder.c
+++ b/src/liblzma/common/block_encoder.c
@@ -161,6 +161,11 @@
 {
 	lzma_next_coder_init(&lzma_block_encoder_init, next, allocator);
 
+	if (block == NULL)
+		return LZMA_PROG_ERROR;
+
+	// The contents of the structure may depend on the version so
+	// check the version first.
 	if (block->version != 0)
 		return LZMA_OPTIONS_ERROR;
 
diff --git a/src/liblzma/common/stream_buffer_encoder.c b/src/liblzma/common/stream_buffer_encoder.c
index 0542c30..2450ee2 100644
--- a/src/liblzma/common/stream_buffer_encoder.c
+++ b/src/liblzma/common/stream_buffer_encoder.c
@@ -51,6 +51,9 @@
 			|| out_pos_ptr == NULL || *out_pos_ptr > out_size)
 		return LZMA_PROG_ERROR;
 
+	if (!lzma_check_is_supported(check))
+		return LZMA_UNSUPPORTED_CHECK;
+
 	// Note for the paranoids: Index encoder prevents the Stream from
 	// getting too big and still being accepted with LZMA_OK, and Block
 	// encoder catches if the input is too big. So we don't need to
diff --git a/src/liblzma/lzma/lzma2_decoder.c b/src/liblzma/lzma/lzma2_decoder.c
index f38879c..3e42575 100644
--- a/src/liblzma/lzma/lzma2_decoder.c
+++ b/src/liblzma/lzma/lzma2_decoder.c
@@ -67,6 +67,10 @@
 		const uint32_t control = in[*in_pos];
 		++*in_pos;
 
+		// End marker
+		if (control == 0x00)
+			return LZMA_STREAM_END;
+
 		if (control >= 0xE0 || control == 1) {
 			// Dictionary reset implies that next LZMA chunk has
 			// to set new properties.
@@ -104,10 +108,6 @@
 							&coder->options);
 			}
 		} else {
-			// End marker
-			if (control == 0x00)
-				return LZMA_STREAM_END;
-
 			// Invalid control values
 			if (control > 2)
 				return LZMA_DATA_ERROR;
diff --git a/src/scripts/xzgrep.in b/src/scripts/xzgrep.in
index cbc6b23..dd94513 100644
--- a/src/scripts/xzgrep.in
+++ b/src/scripts/xzgrep.in
@@ -27,7 +27,7 @@
 xz='@xz@ --format=auto'
 unset GZIP BZIP BZIP2
 
-case ${0##/*} in
+case ${0##*/} in
   *egrep*) prog=xzegrep; grep=${GREP:-egrep};;
   *fgrep*) prog=xzfgrep; grep=${GREP:-fgrep};;
   *)       prog=xzgrep; grep=${GREP:-grep};;
@@ -35,7 +35,7 @@
 
 version="$prog (@PACKAGE_NAME@) @VERSION@"
 
-usage="Usage: ${0##/*} [OPTION]... [-e] PATTERN [FILE]...
+usage="Usage: ${0##*/} [OPTION]... [-e] PATTERN [FILE]...
 Look for instances of PATTERN in the input FILEs, using their
 uncompressed contents if they are compressed.
 
diff --git a/tests/files/README b/tests/files/README
index 108ce8f..53950ed 100644
--- a/tests/files/README
+++ b/tests/files/README
@@ -87,6 +87,10 @@
     uncompressed with dictionary reset, and third is LZMA with new
     properties but without dictionary reset.
 
+    good-1-lzma2-5.xz has an empty LZMA2 stream with only the end of
+    payload marker. XZ Utils 5.0.1 and older incorrectly see this file
+    as corrupt.
+
     good-1-3delta-lzma2.xz has three Delta filters and LZMA2.
 
 
diff --git a/tests/files/good-1-lzma2-5.xz b/tests/files/good-1-lzma2-5.xz
new file mode 100644
index 0000000..339d1c3
--- /dev/null
+++ b/tests/files/good-1-lzma2-5.xz
Binary files differ