From c4ef7baabb7312ee01378af15400a7cc08846de2 Mon Sep 17 00:00:00 2001
From: bunnie <bunnie@kosagi.com>
Date: Sat, 6 Dec 2025 18:21:57 +0800
Subject: [PATCH] add image size checking in image generator

flags when the kernel is too big now
---
 tools/src/sign_image.rs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tools/src/sign_image.rs b/tools/src/sign_image.rs
index 0452570b1..ebe04aec1 100644
--- a/tools/src/sign_image.rs
+++ b/tools/src/sign_image.rs
@@ -255,6 +255,19 @@ pub fn sign_image(
             }
 
             dest_file.write_all(&protected)?;
+
+            if function_code == FunctionCode::Kernel {
+                let target = bao1x_api::RRAM_STORAGE_LEN - (bao1x_api::KERNEL_START - bao1x_api::BOOT0_START);
+                if dest_file.len() > target {
+                    println!(
+                        "ERROR: Xous RRAM image is too big to fit: {} bytes too large ({} bytes; {} limit)",
+                        dest_file.len() - target,
+                        dest_file.len(),
+                        target,
+                    );
+                    return Err(String::from("Image doesn't fit").into());
+                }
+            }
             Ok(dest_file)
         }
     }