--- fwmaker/src/fwmaker.c	2026/01/04 18:08:18	1.1.1.1
+++ fwmaker/src/fwmaker.c	2026/01/04 18:52:50	1.2
@@ -8,6 +8,7 @@ struct tagMtd mtd;
 char image[MAXPATHLEN];
 int imgfd;
 size_t imgsiz;
+u_char fillCh = 0x0;
 
 
 void
@@ -16,8 +17,9 @@ Usage()
 	printf(	" -= FWMAKER =- Firmware maker software ver.%s\n"
 		" (C)`25 ELWIX by Michael Pounov <misho@elwix.org> \n"
 		"==================================================\n"
-		" Syntax: fwmaker [-options] <image> [commands]\n\n"
+		" Syntax: fwmaker [-options] <image> [command [args]]\n\n"
 		"\t-i\t\t\tPrompt command\n"
+		"\t-C <byte>\t\tFill empty bytes [default=0x0]\n"
 		"\t-d <0xmask>\t\tDebug mode\n"
 		"\t-v\t\t\tVerbose, more -v more verbosity\n"
 		"\t-h\t\t\tHelp, this screen\n", "0.1");
@@ -29,6 +31,9 @@ prepareCli()
 	cli_addCommand(line, "image", 1, cmd_Image, "image command", "image management");
 	cli_addCommand(line, "mtd", 1, cmd_Mtd, "mtd command", "mtd partition");
 	cli_addCommand(line, "show", 1, cmd_Show, "show command", "shows parameters");
+
+	cli_addCommand(line, "fill_byte", 2, cmd_FillCh, "fill_byte command",
+			"fill image empty areas with byte");
 }
 
 int
@@ -37,8 +42,11 @@ main(int argc, char **argv)
 	int ch, imode = 0, ret = 0;
 	char **args, cmdline[BUFSIZ] = { 0 };
 
-	while ((ch = getopt(argc, argv, "hvid:")) != -1)
+	while ((ch = getopt(argc, argv, "hvid:C:")) != -1)
 		switch (ch) {
+			case 'C':
+				fillCh = (u_char) strtol(optarg, NULL, 0);
+				break;
 			case 'i':
 				imode = 42;
 				break;