diff --git a/web-ui/code.js b/web-ui/code.js
index 4eba25f..680482a 100644
--- a/web-ui/code.js
+++ b/web-ui/code.js
@@ -1567,6 +1567,12 @@ async function csbCompileOnly() {
       const kb = data.size ? (data.size / 1024).toFixed(1) : null;
       const extra = data.autoInstalled?.length ? `\n자동 설치된 라이브러리: ${data.autoInstalled.join(', ')}` : '';
       codeAiAppend('system', `✅ 컴파일 성공${kb ? ` (${kb} KB)` : ''} — 오류 없음.${extra}`);
+      // 업로드 패널에서 재컴파일 없이 바로 업로드할 수 있도록 캐시
+      _cupCompiledData = data;
+      _cupCompiledForCode = code;
+      _cupCompiledForFqbn = _csbSelBoard.fqbn;
+      _cupCode = code; _cupFqbn = _csbSelBoard.fqbn;
+      _cupBoardName = _csbSelBoard.name; _cupFname = file.name;
     }
   } catch (e) {
     codeAiAppend('system', `컴파일 오류: ${e.message}`);
@@ -5825,6 +5831,8 @@ let _cupPort = null;
 let _cupBusy = false;
 let _cupCode = '', _cupFqbn = '', _cupBoardName = '', _cupFname = '';
 let _cupCompiledData = null;
+let _cupCompiledForCode = '';
+let _cupCompiledForFqbn = '';
 let _cupBoardOptions = [];
 let _cupSelOptions = {};
 let _cupMonActive = false;
@@ -5999,12 +6007,20 @@ async function _cupCompile() {
   if (data.error) { cupLog('컴파일 오류:\n' + data.error, 'err'); _cupSetStatus('error', '컴파일 실패'); return null; }
   const kb = data.size ? ` (${(data.size/1024).toFixed(1)} KB)` : '';
   cupLog(`✅ 컴파일 완료${kb}`, 'ok');
+  _cupCompiledForCode = _cupCode;
+  _cupCompiledForFqbn = _cupGetEffectiveFqbn();
   return data;
 }
 
+function _cupCacheHit() {
+  return _cupCompiledData && _cupCompiledForCode === _cupCode && _cupCompiledForFqbn === _cupGetEffectiveFqbn();
+}
+
 async function cupDoDownload() {
   cupTab('log');
-  const data = await _cupCompile(); if (!data) return;
+  let data;
+  if (_cupCacheHit()) { data = _cupCompiledData; cupLog('캐시된 컴파일 결과 사용', 'info'); }
+  else { data = await _cupCompile(); if (!data) return; }
   _cupCompiledData = data;
   const isHex = !!data.hex;
   const content = isHex ? data.hex : _cupBase64ToBytes(data.bin || data.merged);
@@ -6030,8 +6046,9 @@ async function cupDoUpload() {
   document.getElementById('cup-tab-log').innerHTML = '';
   _cupSetProgress(0);
   try {
-    const data = await _cupCompile(); if (!data) return;
-    _cupCompiledData = data;
+    let data;
+    if (_cupCacheHit()) { data = _cupCompiledData; cupLog('캐시된 컴파일 결과 사용', 'info'); }
+    else { data = await _cupCompile(); if (!data) return; _cupCompiledData = data; }
     cupLog(`\n--- 업로드 시작 [${_cupBoardName}] ---`, 'prog'); _cupSetStatus('uploading', '업로드 중...'); _cupSetProgress(5);
     if (method === 'avr-stk500')   await _cupUploadAVR(data.hex);
     else if (method === 'stm32-uart') await _cupUploadSTM32(_cupBase64ToBytes(data.bin));
@@ -6047,8 +6064,9 @@ async function _cupUploadESP32() {
   _cupSetProgress(0);
   let transport = null, success = false;
   try {
-    const data = await _cupCompile(); if (!data) return;
-    _cupCompiledData = data;
+    let data;
+    if (_cupCacheHit()) { data = _cupCompiledData; cupLog('캐시된 컴파일 결과 사용', 'info'); }
+    else { data = await _cupCompile(); if (!data) return; _cupCompiledData = data; }
     const b64 = data.merged || data.bin;
     if (!b64) throw new Error('컴파일 결과에 바이너리가 없습니다');
     cupLog('esptool-js 로딩 중...', 'prog');