diff --git a/system/fastboot/fastboot.c b/system/fastboot/fastboot.c
index d443bb9c879..83b29528446 100644
--- a/system/fastboot/fastboot.c
+++ b/system/fastboot/fastboot.c
@@ -870,6 +870,7 @@ static int fastboot_filedump_upload(FAR struct fastboot_ctx_s *ctx)
 static void fastboot_filedump(FAR struct fastboot_ctx_s *ctx,
                               FAR const char *arg)
 {
+  char format[64];
   struct stat sb;
   int ret;
 
@@ -879,7 +880,10 @@ static void fastboot_filedump(FAR struct fastboot_ctx_s *ctx,
       return;
     }
 
-  ret = sscanf(arg, "%s %" PRIdOFF " %zu", ctx->upload_param.u.file.path,
+  snprintf(format, sizeof(format), "%%%zus %%" PRIdOFF " %%zu",
+           sizeof(ctx->upload_param.u.file.path) - 1);
+
+  ret = sscanf(arg, format, ctx->upload_param.u.file.path,
                &ctx->upload_param.u.file.offset, &ctx->upload_param.size);
   if (ret != 1 && ret != 3)
     {