now we unzip downloaded autoupdate zip file in two steps:

1. all files except `rusefi_autouppdate.jar` before new class loader preparation
2. `rusefi_autouppdate.jar` after new class loader preparation
(closes #6777)

java_console/autoupdate/src/main/java/com/rusefi/autoupdate/Autoupdate.java

@@ -25,6 +25,8 @@ import java.util.Optional;
 import java.util.Properties;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Predicate;
+import java.util.zip.ZipEntry;
 
 import static com.devexperts.logging.Logging.getLogging;
 import static com.rusefi.core.FindFileHelper.findSrecFile;
@@ -105,16 +107,18 @@ public class Autoupdate {
         }
         downloadedAutoupdateFile.ifPresent(autoupdateFile -> {
             try {
-                FileUtil.unzip(autoupdateFile.zipFileName, new File(".."));
+                // We cannot unzip rusefi_autoupdate.jar file because we need the old one to prepare class loader below
+                // (otherwise we get `ZipFile invalid LOC header (bad signature)` exception, see #6777)
+                FileUtil.unzip(autoupdateFile.zipFileName, new File(".."), isRusefiAutoupdateJar.negate());
                 final String srecFile = findSrecFile();
                 new File(srecFile == null ? FindFileHelper.FIRMWARE_BIN_FILE : srecFile)
                     .setLastModified(autoupdateFile.lastModified);
             } catch (IOException e) {
-                log.error("Error unzipping bundle: " + e);
+                log.error("Error unzipping bundle without rusefi_autoupdate.jar: " + e);
                 if (!AutoupdateUtil.runHeadless) {
                     JOptionPane.showMessageDialog(
                         null,
-                        "Error unzipping bundle " + e,
+                        "Error unzipping bundle without rusefi_autoupdate.jar: " + e,
                         "Error",
                         JOptionPane.ERROR_MESSAGE
                     );
@@ -122,9 +126,28 @@ public class Autoupdate {
             }
         });
         final URLClassLoader jarClassLoader = prepareClassLoaderToStartConsole();
+        downloadedAutoupdateFile.ifPresent(autoupdateFile -> {
+            try {
+                // We've already prepared class loader, so now we can unzip rusefi_autoupdate.jar file (#6777)
+                FileUtil.unzip(autoupdateFile.zipFileName, new File(".."), isRusefiAutoupdateJar);
+            } catch (IOException e) {
+                log.error("Error unzipping rusefi_autoupdate.jar from bundle: " + e);
+                if (!AutoupdateUtil.runHeadless) {
+                    JOptionPane.showMessageDialog(
+                        null,
+                        "Error unzipping rusefi_autoupdate.jar from bundle: " + e,
+                        "Error",
+                        JOptionPane.ERROR_MESSAGE
+                    );
+                }
+            }
+        });
         startConsole(args, jarClassLoader);
     }
 
+    private static final Predicate<ZipEntry> isRusefiAutoupdateJar =
+        zipEntry -> "console/rusefi_autoupdate.jar".equals(zipEntry.getName());
+
     private static Optional<DownloadedAutoupdateFileInfo> doDownload(
         final BundleUtil.BundleInfo bundleInfo,
         final UpdateMode mode

java_console/shared_io/src/main/java/com/rusefi/core/FileUtil.java

@@ -5,6 +5,7 @@ import org.jetbrains.annotations.NotNull;
 import java.io.*;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.util.function.Predicate;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
@@ -14,7 +15,11 @@ import java.util.zip.ZipInputStream;
 public class FileUtil {
     public static final String RUSEFI_SETTINGS_FOLDER = System.getProperty("user.home") + File.separator + ".rusEFI";
 
-    public static void unzip(String zipFileName, File destDir) throws IOException {
+    public static void unzip(
+        final String zipFileName,
+        final File destDir,
+        final Predicate<ZipEntry> filter
+    ) throws IOException {
         byte[] buffer = new byte[1024];
         ZipInputStream zis = new ZipInputStream(new FileInputStream(zipFileName));
         ZipEntry zipEntry = zis.getNextEntry();
@@ -24,6 +29,7 @@ public class FileUtil {
              * apache commons compress does
              * https://stackoverflow.com/questions/1050560/maintain-file-permissions-when-extracting-from-a-zip-file-using-jdk-5-api
              */
+            if (filter.test(zipEntry)) {
                 File newFile = newFile(destDir, zipEntry);
                 if (zipEntry.isDirectory()) {
                     if (!newFile.isDirectory()) {
@@ -34,6 +40,7 @@ public class FileUtil {
                 } else {
                     unzipFile(buffer, zis, newFile);
                 }
+            }
             zipEntry = zis.getNextEntry();
         }
         zis.closeEntry();