diff --git a/cli/lz/build.sh b/cli/lz/build.sh
index bd31f63..eaecffc 100755
--- a/cli/lz/build.sh
+++ b/cli/lz/build.sh
@@ -1,5 +1,9 @@
 #!/bin/sh -e
 
+RELEASE_flags="-DNDEBUG -O2 -g0 -s"
+DEBUG_flags="-std=c89 -D_POSIX_C_SOURCE=199309L -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werror=implicit-int -Werror=incompatible-pointer-types -Werror=int-conversion -Wvla -g -Og -fsanitize=address -fsanitize=undefined"
+
+
 LIN="uxncli $HOME/roms/uxnlin.rom"
 ASM="uxncli $HOME/roms/drifblim.rom"
 
@@ -7,12 +11,12 @@ if [[ "$*" == *"--lint"* ]]
 then
 	$LIN decoder.tal
 	clang-format -i lz_main.c
+	clang-format -i ulzcdec.c
 fi
 
 # Make c file
 
-cc lz_main.c -o main && ./main
-./main # read example.txt, write compressed.bin
+cc lz_main.c -o main && ./main && ./main # read example.txt, write compressed.bin
 
 # Decoding
 
diff --git a/cli/lz/ulzdec.c b/cli/lz/ulzdec.c
new file mode 100644
index 0000000..60cffbd
--- /dev/null
+++ b/cli/lz/ulzdec.c
@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+/* cc ulzdec.c -o ulzdec && ./ulzdec compressed.bin */
+
+static int
+error(const char *name, const char *msg)
+{
+	fprintf(stderr, "%s: %s\n", name, msg);
+	return 0;
+}
+
+void
+decode_byte(FILE *fp, char *res, unsigned char c)
+{
+	if(c & 0x80) {
+		if(c & 0x40) { /* DICT3 */
+			unsigned short length = ((c & 0x3f) << 8 | getc(fp)) + 4;
+			unsigned char offset = getc(fp) + 1;
+			printf("DIC3  %04x, %02x\n", length, offset);
+		} else { /* DICT2 */
+			unsigned char length = (c & 0x3f) + 4;
+			unsigned char offset = getc(fp) + 1;
+			printf("DIC1  %02x, %02x\n", length, offset);
+		}
+	} else { /* LIT */
+		unsigned char i, length = c + 1;
+		printf("LIT%02x ", length);
+		for(i = 0; i < length; ++i) {
+			unsigned char c2 = getc(fp);
+			printf("%c", c2 == '\n' ? ' ' : c2);
+		}
+		printf("\n");
+	}
+}
+
+int
+main(int argc, char *argv[])
+{
+	char c, *res;
+	FILE *src;
+	if(argc == 2 && argv[1][0] == '-' && argv[1][1] == 'v')
+		return !fprintf(stdout, "Ulzdec - ULZ Decoder, 15 Nov 2023.\n");
+	if(argc != 2)
+		return error("usage", "ulzdec [-v] compressed.bin");
+	if(!(src = fopen(argv[1], "rb")))
+		return !error("Invalid input", argv[1]);
+	res = malloc(0x10000);
+	while((c = getc(src)) != EOF)
+		decode_byte(src, res, c);
+	return 0;
+}
\ No newline at end of file