diff --git a/src/flash/nor/str9x.c b/src/flash/nor/str9x.c
index 7d93b187d..2158622a1 100644
--- a/src/flash/nor/str9x.c
+++ b/src/flash/nor/str9x.c
@@ -392,9 +392,10 @@ static int str9x_write_block(struct flash_bank *bank,
 		return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
 	};
 
-	target_write_buffer(target, write_algorithm->address,
-			sizeof(str9x_flash_write_code),
-			(uint8_t *)str9x_flash_write_code);
+	uint8_t code[sizeof(str9x_flash_write_code)];
+	target_buffer_set_u32_array(target, code, ARRAY_SIZE(str9x_flash_write_code),
+			str9x_flash_write_code);
+	target_write_buffer(target, write_algorithm->address, sizeof(code), code);
 
 	/* memory buffer */
 	while (target_alloc_working_area_try(target, buffer_size, &source) != ERROR_OK) {