diff --git a/src/avrdude/config.c b/src/avrdude/config.c
index 0dec3c47b..0ad12dce7 100644
--- a/src/avrdude/config.c
+++ b/src/avrdude/config.c
@@ -364,7 +364,7 @@ int read_config_builtin()
   // Note: Can't use yy_scan_buffer, it's buggy (?), leads to fread from a null FILE*
   // and so unfortunatelly we have to use the copying variant here
   // note: changed for avrdude_slic3r_conf_SIZE but i can't build with uper case... if you need it on your os, please use a #ifndef
-  YY_BUFFER_STATE buffer = yy_scan_bytes((const char *)avrdude_slic3r_conf, avrdude_slic3r_conf_size);
+  YY_BUFFER_STATE buffer = yy_scan_bytes((const char *)avrdude_slic3r_conf, avrdude_slic3r_conf_SIZE);
   if (buffer == NULL) {
     avrdude_message(MSG_INFO, "%s: read_config_builtin: Failed to initialize parsing buffer\n", progname);
     return -1;