diff --git a/src/flash/nor/tcl.c b/src/flash/nor/tcl.c
index b4f375fe7..95ca8192f 100644
--- a/src/flash/nor/tcl.c
+++ b/src/flash/nor/tcl.c
@@ -506,7 +506,7 @@ COMMAND_HANDLER(handle_flash_fill_command)
 	if (count == 0)
 		return ERROR_OK;
 
-	if (address + count >= bank->base + bank->size) {
+	if (address + count * wordsize > bank->base + bank->size) {
 		LOG_ERROR("Cannot cross flash bank borders");
 		return ERROR_FAIL;
 	}