diff --git a/lib_generic/lzma/LzmaTools.c b/lib_generic/lzma/LzmaTools.c
index f01e827..5e69eb8 100644
--- a/lib_generic/lzma/LzmaTools.c
+++ b/lib_generic/lzma/LzmaTools.c
@@ -57,6 +57,7 @@
 	int i;
 
 	SizeT outSizeFull = 0xFFFFFFFF; /* 4GBytes limit */
+	SizeT outAvail;
 	SizeT inProcessed;
 	SizeT outProcessed;
 	SizeT outSize;
@@ -101,15 +102,25 @@
 		 */
 	        outSizeFull |= (((SizeT)outSizeHigh << 16) << 16);
 	} else if (outSizeHigh != 0 || (UInt32)(SizeT)outSize != outSize) {
-	        /*
+		/*
 		 * SizeT is a 32 bit uint => We cannot manage files larger than
-		 * 4GB!
+		 * 4GB!  Assume however that all 0xf values is "unknown size" and
+		 * not actually a file of 2^64 bits.
 		 *
 		 */
-		debug ("LZMA: 64bit support not enabled.\n");
-	        return LZMA_RESULT_DATA_ERROR;
+		if (outSizeHigh != (SizeT)-1 || outSize != (SizeT)-1) {
+			debug ("LZMA: 64bit support not enabled.\n");
+			return LZMA_RESULT_DATA_ERROR;
+		}
 	}
 
+	/* Short-circuit early if we know the buffer can't hold the results. */
+	if (outSizeFull != (SizeT)-1 && *uncompressedSize < outSizeFull)
+		return LZMA_RESULT_DATA_ERROR;
+
+	outAvail = min(outSizeFull, *uncompressedSize);
+
+	debug ("LZMA: Available output buffer..... 0x%lx\n", (unsigned long) outAvail);
 	debug ("LZMA: Uncompresed size............ 0x%lx\n", (unsigned long) outSizeFull);
 	debug ("LZMA: Compresed size.............. 0x%lx\n", (unsigned long) compressedSize);
 
@@ -117,7 +128,7 @@
 	debug ("LZMA: Decompress buffer needed.... 0x%lx\n",
 			(unsigned long) LzmaGetNumProbs(&state.Properties) * sizeof(CProb));
 	/* decompression buffer lives at the end of the decompressed image area */
-	state.Probs = (void*)(((unsigned long) outStream + outSizeFull + 0x80) & ~(0x80 - 1));
+	state.Probs = (void*)(((unsigned long) outStream + outAvail + 0x80) & ~(0x80 - 1));
 #else
 	debug ("LZMA: Dynamic memory needed....... 0x%lx, allocating...\n",
 			(unsigned long) LzmaGetNumProbs(&state.Properties) * sizeof(CProb));
@@ -140,11 +151,25 @@
 
 	res = LzmaDecode(&state,
 		inStream + LZMA_DATA_OFFSET, compressedSize, &inProcessed,
-		outStream, outSizeFull,  &outProcessed);
+		outStream, outAvail,  &outProcessed);
 	if (res != LZMA_RESULT_OK)  {
 		return res;
 	}
 
+	debug ("LZMA: Uncompressed bytes out...... 0x%lx\n", (unsigned long) outProcessed);
+	debug ("LZMA: Compressed bytes in......... 0x%lx\n", (unsigned long) inProcessed);
+
+	if (outProcessed != outSizeFull && outProcessed == outAvail) {
+		/*
+		 * If the size of the uncompressed image matches exactly the
+		 * size of the output buffer, then we do not know whether that
+		 * is a just coincident or whether LzmaDecode stopped
+		 * prematurely due to insufficient output buffer space. Err on
+		 * the side of caution and return an error.
+		 * */
+		return LZMA_RESULT_DATA_ERROR;
+	}
+
 	*uncompressedSize = outProcessed;
 #ifndef LZMA_DECOMPRESS_NOALLOC
 	free(state.Probs);