diff --git a/src/p7os/args.c b/src/p7os/args.c
index 293beae..1a53066 100644
--- a/src/p7os/args.c
+++ b/src/p7os/args.c
@@ -70,6 +70,7 @@ static const char help_main1[] =
 "                     If this option isn't used, the program will look for a\n"
 "                     calculator connected using direct USB.\n"
 "  --no-prepare       Use the current environment, instead of uploading one.\n"
+"  --erase-flash      Instead of 0xA0270000 the last erase addr is 0xA0400000.\n"
 "  -u, --uexe <path>  Use a custom update program.\n"
 "                     If `--no-prepare` is not given, this option is "
 	"required.\n"
@@ -181,6 +182,7 @@ static const struct option longopts[] = {
 	{"version",          no_argument, NULL, 'v'},
 	{"com",        required_argument, NULL, 'c'},
 	{"no-prepare",       no_argument, NULL, 'n'},
+	{"erase-flash",      no_argument, NULL, 'e'},
 	{"uexe",       required_argument, NULL, 'u'},
 	{"output",     required_argument, NULL, 'o'},
 	{"log",        required_argument, NULL, 'l'},
@@ -225,7 +227,7 @@ int parse_args(int ac, char **av, args_t *args)
 			version = 1;
 			break;
 
-		/* COM port, should prepare or not. */
+		/* COM port, should prepare or not, should erase flash or not. */
 
 		case 'c':
 			args->com = optarg;
@@ -233,6 +235,9 @@ int parse_args(int ac, char **av, args_t *args)
 		case 'n':
 			args->noprepare = 1;
 			break;
+		case 'e':
+			args->eraseflash = 1;
+			break;
 
 		/* log level, Update.Exe, output path */
 
diff --git a/src/p7os/main.h b/src/p7os/main.h
index c66e309..7000335 100644
--- a/src/p7os/main.h
+++ b/src/p7os/main.h
@@ -38,6 +38,7 @@ enum menu_e {
 typedef struct {
 	enum menu_e  menu;
 	int noprepare;
+	int eraseflash;
 
 	/* communication and tweaks */
 	const char *com;
diff --git a/src/p7os/procs/fxremote_flash.c b/src/p7os/procs/fxremote_flash.c
index fd703a3..2b19105 100644
--- a/src/p7os/procs/fxremote_flash.c
+++ b/src/p7os/procs/fxremote_flash.c
@@ -177,11 +177,11 @@ int fxremote_flash(args_t *args)
 	 * Maybe it just ANDs, or something...? Anyway, I'll do it as well. */
 
 	{
-		int num = 1, total = (top - 0xA0010000) / 0x10000;
+		int num = 1, total = ((args->eraseflash ? 0xA0280000 : top) - 0xA0010000) / 0x10000;
 
 		osdisp_init(&osdisp_cookie, "Clearing the sectors.", "Cleared!");
 		osdisp(&osdisp_cookie, 1, 0);
-		for (addr = 0xA0010000; addr < top; addr += 0x10000) {
+		for (addr = 0xA0010000; addr < (args->eraseflash ? 0xA0280000 : top); addr += 0x10000) {
 			casio_uint32_t localaddr;
 
 			localaddr = casio_htobe32(addr);