diff --git a/kiwi/bootloader/config/grub2.py b/kiwi/bootloader/config/grub2.py
index 91fac73a68..673442d7e6 100644
--- a/kiwi/bootloader/config/grub2.py
+++ b/kiwi/bootloader/config/grub2.py
@@ -66,6 +66,8 @@ def post_init(self, custom_args):
 
                 {'grub_directory_name': 'grub|grub2'}
         """
+        self.efi_csm = True if self.xml_state.build_type.get_eficsm() is None \
+            else self.xml_state.build_type.get_eficsm()
         self.custom_args = custom_args
         self.config_options = []
         arch = Defaults.get_platform_name()
@@ -612,7 +614,9 @@ def _copy_grub_config_to_efi_path(
             )
 
     def _supports_bios_modules(self):
-        if self.arch == 'ix86' or self.arch == 'x86_64' or Defaults.is_ppc64_arch(self.arch):
+        if self.efi_csm and (
+            self.arch == 'ix86' or self.arch == 'x86_64' or Defaults.is_ppc64_arch(self.arch)
+        ):
             return True
         return False
 
diff --git a/kiwi/package_manager/apt.py b/kiwi/package_manager/apt.py
index 25e8fa1ffc..12f01f20e0 100644
--- a/kiwi/package_manager/apt.py
+++ b/kiwi/package_manager/apt.py
@@ -557,17 +557,19 @@ def _run_bootstrap_scripts(
             script_post = f'{package_metadata_dir}/postinst'
             # 1. preinst
             if os.path.exists(script_pre):
+                Command.run(['chmod', '755', script_pre])
                 Command.run(
                     [
-                        'chroot', self.root_dir, 'bash',
+                        'chroot', self.root_dir,
                         f'{script_pre.replace(self.root_dir, "")}', 'install'
                     ], self.command_env
                 )
             # 2. postinst
             if os.path.exists(script_post):
+                Command.run(['chmod', '755', script_post])
                 Command.run(
                     [
-                        'chroot', self.root_dir, 'bash',
+                        'chroot', self.root_dir,
                         f'{script_post.replace(self.root_dir, "")}', 'configure'
                     ], self.command_env
                 )
diff --git a/test/unit/package_manager/apt_test.py b/test/unit/package_manager/apt_test.py
index 1f2bada443..28fd8286b8 100644
--- a/test/unit/package_manager/apt_test.py
+++ b/test/unit/package_manager/apt_test.py
@@ -182,13 +182,23 @@ def test_process_install_requests_bootstrap(
             ),
             call(
                 [
-                    'chroot', 'root-dir', 'bash',
+                    'chmod', '755', 'tempdir/base-passwd/preinst'
+                ]
+            ),
+            call(
+                [
+                    'chroot', 'root-dir',
                     'tempdir/base-passwd/preinst', 'install'
                 ], new_env
             ),
             call(
                 [
-                    'chroot', 'root-dir', 'bash',
+                    'chmod', '755', 'tempdir/base-passwd/postinst'
+                ]
+            ),
+            call(
+                [
+                    'chroot', 'root-dir',
                     'tempdir/base-passwd/postinst', 'configure'
                 ], new_env
             ),
@@ -197,13 +207,23 @@ def test_process_install_requests_bootstrap(
             ),
             call(
                 [
-                    'chroot', 'root-dir', 'bash',
+                    'chmod', '755', 'tempdir/base-passwd/preinst'
+                ]
+            ),
+            call(
+                [
+                    'chroot', 'root-dir',
                     'tempdir/base-passwd/preinst', 'install'
                 ], new_env
             ),
             call(
                 [
-                    'chroot', 'root-dir', 'bash',
+                    'chmod', '755', 'tempdir/base-passwd/postinst'
+                ]
+            ),
+            call(
+                [
+                    'chroot', 'root-dir',
                     'tempdir/base-passwd/postinst', 'configure'
                 ], new_env
             ),
@@ -212,13 +232,23 @@ def test_process_install_requests_bootstrap(
             ),
             call(
                 [
-                    'chroot', 'root-dir', 'bash',
+                    'chmod', '755', 'tempdir/vim/preinst'
+                ]
+            ),
+            call(
+                [
+                    'chroot', 'root-dir',
                     'tempdir/vim/preinst', 'install'
                 ], new_env
             ),
             call(
                 [
-                    'chroot', 'root-dir', 'bash',
+                    'chmod', '755', 'tempdir/vim/postinst'
+                ]
+            ),
+            call(
+                [
+                    'chroot', 'root-dir',
                     'tempdir/vim/postinst', 'configure'
                 ], new_env
             )