diff --git a/.gitignore b/.gitignore
index d7a1ba1..a998bf7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,3 +26,7 @@ cargo.lock
 *.a2h
 *.bin
 /tmp.a2l
+/a2lfile.a2l
+/a2lfile.txt
+/test.a2l
+/xcp_lite.a2l
diff --git a/tests/multi_thread.rs b/tests/multi_thread.rs
index 1809669..adc438f 100644
--- a/tests/multi_thread.rs
+++ b/tests/multi_thread.rs
@@ -212,7 +212,7 @@ async fn test_multi_thread() {
     }
 
     thread::sleep(Duration::from_millis(250)); // Wait to give all threads a chance to initialize and enter their loop
-    test_executor(xcp, test_executor::TestMode::MultiThreadDAQ, "test_multi_thread.a2l", false).await; // Start the test executor XCP client
+    test_executor(xcp, test_executor::TestMode::MultiThreadDAQ, "test_multi_thread.a2l", true).await; // Start the test executor XCP client
 
     info!("Test done. Waiting for tasks to terminate");
     for t in v {
diff --git a/tests/tokio_multi_thread.rs b/tests/tokio_multi_thread.rs
index 0a9b017..820befe 100644
--- a/tests/tokio_multi_thread.rs
+++ b/tests/tokio_multi_thread.rs
@@ -185,7 +185,7 @@ async fn test_tokio_multi_thread() {
         v.push(t);
     }
 
-    test_executor(xcp, test_executor::TestMode::MultiThreadDAQ, "test_tokio_multi_thread.a2l", false).await; // Start the test executor XCP client
+    test_executor(xcp, test_executor::TestMode::MultiThreadDAQ, "test_tokio_multi_thread.a2l", true).await; // Start the test executor XCP client
 
     for t in v {
         t.join().ok();
diff --git a/xcplib/xcpAppl.c b/xcplib/xcpAppl.c
index 3ac2c04..40b5734 100644
--- a/xcplib/xcpAppl.c
+++ b/xcplib/xcpAppl.c
@@ -386,15 +386,12 @@ uint8_t ApplXcpGetCalPageMode(uint8_t segment) {
 #endif
 
 /**************************************************************************/
-// Provide infos for GET_ID
-// The XCP command GET_ID provides different type of identification
-// information to the XCP client
-// Returns 0, when the information is not available
+// Functions for upload of A2L file
 /**************************************************************************/
 
-static const char *gXcpA2lName = NULL; // A2L filename
+static const char *gXcpA2lName = NULL; // A2L filename (without extension .a2l)
 
-// This is used by the Rust ffi bindings only
+// This is used by the Rust ffi to set the A2L name generated by the registry
 void ApplXcpSetA2lName(const char *name) {
     DBG_PRINTF3("Set A2L name to '%s'\n", name);
     gXcpA2lName = (char*)name; // must be static lifetime
@@ -402,83 +399,50 @@ void ApplXcpSetA2lName(const char *name) {
 
 #ifdef XCP_ENABLE_IDT_A2L_UPLOAD // Enable GET_ID A2L content upload to host
 
-static uint8_t* gXcpFile = NULL; // A2l file content
+static FILE* gXcpFile = NULL; // A2l file content
 static uint32_t gXcpFileLength = 0; // A2L file length
 
-BOOL ApplXcpReadA2L(uint8_t size, uint32_t addr, uint8_t* data) {
-  if (addr + size > gXcpFileLength) return FALSE;
-  memcpy(data, gXcpFile + addr, size);
-  return TRUE;
-}
-
-// @@@@ ToDo: Implement a way to release the file memory after upload
-/*
-static void releaseFile(uint8_t* file) {
 
-  if (file != NULL) {
-    free(file);
-  }
+void closeA2lFile() {
+    assert(gXcpFile != NULL);
+    fclose(gXcpFile);
+    gXcpFile = NULL;
+    DBG_PRINT3("Close A2L file\n");
 }
-*/
-
-static uint8_t* loadFile(const char* filename, uint32_t* length) {
-
-  uint8_t* fileBuf = NULL; // file content
-  uint32_t fileLen = 0; // file length
-
-  DBG_PRINTF3("Load A2L file %s to memory buffer\n", filename);
-
-#if defined(_LINUX) // Linux
-
-  FILE* fd;
-  fd = fopen(filename, "r");
-  if (fd == NULL) {
-    DBG_PRINTF_ERROR("ERROR: file %s not found!\n", filename);
-    return NULL;
-  }
-  struct stat fdstat;
-  stat(filename, &fdstat);
-  fileBuf = (uint8_t*)malloc((size_t)(fdstat.st_size + 1));
-  if (fileBuf == NULL) return NULL;
-  fileLen = (uint32_t)fread(fileBuf, 1, (uint32_t)fdstat.st_size, fd);
-  fclose(fd);
-
-#elif defined(_WIN) // Windows
-
-  wchar_t wcfilename[256] = { 0 };
-  MultiByteToWideChar(0, 0, filename, (int)strlen(filename), wcfilename, (int)strlen(filename));
-  HANDLE hFile = CreateFileW((wchar_t*)wcfilename, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
-  if (hFile == INVALID_HANDLE_VALUE) {
-    DBG_PRINTF_ERROR("ERROR: file %s not found!\n", filename);
-    return NULL;
-  }
-  fileLen = (uint32_t)GetFileSize(hFile, NULL);
-  fileBuf = (uint8_t*)malloc(fileLen + 1);
-  if (fileBuf == NULL) {
-    DBG_PRINTF_ERROR("ERROR: out of memory!\n");
-    CloseHandle(hFile);
-    return NULL;
-  }
-  if (!ReadFile(hFile, fileBuf, fileLen, NULL, NULL)) {
-    DBG_PRINTF_ERROR("ERROR: could not read from %s!\n", filename);
-    free(fileBuf);
-    CloseHandle(hFile);
-    return NULL;
-  }
-  fileBuf[fileLen] = 0;
-  CloseHandle(hFile);
-
-#endif
 
-  DBG_PRINTF3("  file %s ready for upload, size=%u\n\n", filename, fileLen);
-  assert(fileLen > 0);
+uint32_t openA2lFile() {
+    char filename[256];
+    SNPRINTF((char*)filename, 255, "%s.a2l", gXcpA2lName);
+    assert(gXcpFile == NULL);
+    gXcpFile = fopen(filename, "r");
+    if (gXcpFile == NULL) {
+        DBG_PRINTF_ERROR("ERROR: file %s not found!\n", filename);
+        return 0;
+    }
+    struct stat fdstat;
+    stat(filename, &fdstat);
+    gXcpFileLength = (uint32_t)fdstat.st_size;
+    assert(gXcpFileLength > 0);
+    DBG_PRINTF3("A2L file %s ready for upload, size=%u\n\n", filename, gXcpFileLength);
+    return gXcpFileLength;
+}
 
-  *length = fileLen;
-  return fileBuf;
+BOOL ApplXcpReadA2L(uint8_t size, uint32_t addr, uint8_t* data) {
+    if (gXcpFile == NULL) return FALSE;
+    if (addr + size > gXcpFileLength) return FALSE;
+    if (size!=fread(data, 1, (uint32_t)size, gXcpFile)) return FALSE;
+    if (addr + size == gXcpFileLength) closeA2lFile(); // Close file after complete sequential read
+    return TRUE;
 }
 
-#endif
+#endif // XCP_ENABLE_IDT_A2L_UPLOAD
 
+/**************************************************************************/
+// Provide infos for GET_ID
+// The XCP command GET_ID provides different type of identification
+// information to the XCP client
+// Returns 0, when the information is not available
+/**************************************************************************/
 
 uint32_t ApplXcpGetId(uint8_t id, uint8_t* buf, uint32_t bufLen) {
 
@@ -511,10 +475,14 @@ uint32_t ApplXcpGetId(uint8_t id, uint8_t* buf, uint32_t bufLen) {
 #ifdef XCP_ENABLE_IDT_A2L_UPLOAD
     case IDT_ASAM_UPLOAD:
         {
+    #ifdef XCP_LOAD_A2L_FILE
             char filename[256];
             SNPRINTF((char*)filename, 255, "%s.a2l", gXcpA2lName);
             if (NULL==(gXcpFile=loadFile(filename,&gXcpFileLength))) return 0;
             len = gXcpFileLength;
+    #else
+            len = openA2lFile();
+    #endif
         }
         break;
 #endif