Fix GRUB installation timing and environment variable issues

- Move GRUB installation to occur BEFORE unmounting target filesystem
- Install GRUB inside configure_target_system method before cleanup
- Ensure all mount/umount operations use clean environment variables
- Specifically empty LD_PRELOAD variable to prevent PyInstaller interference
- Update partition_disk, mount_target, and install_bootloader methods
- Remove duplicate GRUB installation call from main run method

This ensures GRUB can access the mounted target filesystem and prevents
PyInstaller environment variables from interfering with system calls.

autoinstaller_gui/autoinstallergui.py

@@ -486,10 +486,7 @@ class InstallerWorker(QThread):
 
             self.progress_updated.emit(90)
 
-            # Step 10: Install Bootloader (95%)
-            self.status_updated.emit("Installing bootloader...")
-            self.install_bootloader(target_mount, target_disk)
-            self.step_completed.emit("Bootloader installed")
+            # Step 10: Bootloader installation moved to configure_target_system (before unmount)
 
             self.progress_updated.emit(95)
 
@@ -696,6 +693,8 @@ class InstallerWorker(QThread):
         # Wait for kernel to recognize partitions
         time.sleep(2)
         partprobe_cmd = f'partprobe {target_disk}'
+        # Use clean environment for partprobe as well
+        clean_env = self._clean_env()
         subprocess.run(partprobe_cmd, shell=True, env=clean_env)
 
         # Format partition
@@ -719,6 +718,8 @@ class InstallerWorker(QThread):
                 del clean_env[key]
 
         try:
+            # Use clean environment for mount operations (remove PyInstaller variables)
+            clean_env = self._clean_env()
             result = subprocess.run(mount_cmd, shell=True, capture_output=True, text=True, env=clean_env, check=True)
             self.log("Target mounted successfully")
         except subprocess.CalledProcessError as e:
@@ -984,7 +985,9 @@ class InstallerWorker(QThread):
 
         for cmd, description in mount_operations:
             try:
-                result = subprocess.run(cmd, capture_output=True, text=True, check=True)
+                # Use clean environment for mount operations (remove PyInstaller variables)
+                clean_env = self._clean_env()
+                result = subprocess.run(cmd, capture_output=True, text=True, check=True, env=clean_env)
                 self.log(f"Successfully mounted {description}")
             except subprocess.CalledProcessError as e:
                 # Check if already mounted (common in live systems)
@@ -1051,6 +1054,15 @@ class InstallerWorker(QThread):
         # Configure NTP
         self._configure_ntp(target_mount)
 
+        # Install GRUB bootloader BEFORE unmounting (moved from main run method)
+        self.log("Installing GRUB bootloader...")
+        try:
+            self.install_bootloader(target_mount, self.config['target_disk'])
+            self.log("GRUB bootloader installed successfully")
+        except Exception as e:
+            self.log(f"Warning: GRUB installation failed: {str(e)}")
+            # Continue with installation despite GRUB failure
+
         # Clean up bind mounts
         self.log("Cleaning up bind mounts")
 
@@ -1064,7 +1076,9 @@ class InstallerWorker(QThread):
 
         for mount_point in unmount_operations:
             try:
-                result = subprocess.run(['umount', mount_point], capture_output=True, text=True, check=True)
+                # Use clean environment for unmount operations (remove PyInstaller variables)
+                clean_env = self._clean_env()
+                result = subprocess.run(['umount', mount_point], capture_output=True, text=True, check=True, env=clean_env)
                 self.log(f"Successfully unmounted {mount_point}")
             except subprocess.CalledProcessError as e:
                 # Check if not mounted (common if mount failed earlier)
@@ -1190,12 +1204,15 @@ class InstallerWorker(QThread):
         for key in list(env.keys()):
             if key.startswith(('LD_', 'PYINSTALLER_', 'PYTHON')):
                 del env[key]
+        # Specifically empty LD_PRELOAD as it can interfere with mount operations
+        env['LD_PRELOAD'] = ''
         return env
 
     def install_bootloader(self, target_mount, target_disk):
-        # GRUB installation
+        # GRUB installation with clean environment
         cmd = ['chroot', target_mount, 'grub-install', target_disk]
-        subprocess.run(cmd, check=True)
+        clean_env = self._clean_env()
+        subprocess.run(cmd, check=True, env=clean_env)
         self.log("Bootloader installed")
 
     def run_post_install(self, target_mount):