diff --git a/src/target/stm32f4.c b/src/target/stm32f4.c
index 265fb7c..3e90bac 100644
--- a/src/target/stm32f4.c
+++ b/src/target/stm32f4.c
@@ -46,7 +46,7 @@ const struct command_s stm32f4_cmd_list[] = {
 	 "Erase entire flash memory"},
 	{"option", (cmd_handler)stm32f4_cmd_option, "Manipulate option bytes"},
 	{"psize", (cmd_handler)stm32f4_cmd_psize,
-	 "Configure flash write parallelism: (x8|x16|x32(default))"},
+	 "Configure flash write parallelism: (x8|x16|x32(default)|x64)"},
 	{NULL, NULL, NULL}
 };
 
@@ -676,6 +676,7 @@ static bool stm32f4_cmd_psize(target *t, int argc, char *argv[])
 			}
 		}
 		tc_printf(t, "Flash write parallelism: %s\n",
+		          psize == ALIGN_DWORD ? "x64" :
 		          psize == ALIGN_WORD ? "x32" :
 				  psize == ALIGN_HALFWORD ? "x16" : "x8");
 	} else {
@@ -686,8 +687,10 @@ static bool stm32f4_cmd_psize(target *t, int argc, char *argv[])
 			psize = ALIGN_HALFWORD;
 		} else if (!strcmp(argv[1], "x32")) {
 			psize = ALIGN_WORD;
+		} else if (!strcmp(argv[1], "x64")) {
+			psize = ALIGN_DWORD;
 		} else {
-			tc_printf(t, "usage: monitor psize (x8|x16|x32)\n");
+			tc_printf(t, "usage: monitor psize (x8|x16|x32|x32)\n");
 			return false;
 		}
 		for (struct target_flash *f = t->flash; f; f = f->next) {