diff --git a/archinstoo/archinstoo/lib/disk/device_handler.py b/archinstoo/archinstoo/lib/disk/device_handler.py
index ca2ccba3..293b3377 100644
--- a/archinstoo/archinstoo/lib/disk/device_handler.py
+++ b/archinstoo/archinstoo/lib/disk/device_handler.py
@@ -542,7 +542,7 @@ def _setup_partition(
 
 		if disk.type == PartitionTable.GPT.value:
 			if part_mod.is_root():
-				partition.type_uuid = PartitionGUID.LINUX_ROOT_X86_64.bytes
+				partition.type_uuid = PartitionGUID.linux_root().bytes
 			elif PartitionFlag.LINUX_HOME not in part_mod.flags and part_mod.is_home():
 				partition.setFlag(PartitionFlag.LINUX_HOME.flag_id)
 
diff --git a/archinstoo/archinstoo/lib/installer.py b/archinstoo/archinstoo/lib/installer.py
index aa651d3d..210efd75 100644
--- a/archinstoo/archinstoo/lib/installer.py
+++ b/archinstoo/archinstoo/lib/installer.py
@@ -2552,18 +2552,16 @@ def run_grimoire_installation(
 
 def run_custom_user_commands(commands: list[str], installation: Installer) -> None:
 	for index, command in enumerate(commands):
-		script_path = f'/var/tmp/user-command.{index}.sh'  # noqa: S108 - path inside install target, not host /tmp
-		chroot_path = f'{installation.target}/{script_path}'
+		script_path = LPath(f'/var/tmp/user-command.{index}.sh')  # noqa: S108 - path inside install target, not host /tmp
+		chroot_path = installation.target / script_path.relative_to_root()
 
 		# Do not throw error instead warn
 		info(f'Executing custom command "{command}" ...')
-		chroot_path_p = Path(chroot_path)
-		with chroot_path_p.open('w') as user_script:
-			user_script.write(command)
+		chroot_path.write_text(command)
 
 		try:
 			SysCommand(f'{" ".join(installation._arch_chroot_prefix)} bash {script_path}')
 		except SysCallError as e:
 			warn(f'Custom command "{command}" failed: {e}')
 		finally:
-			chroot_path_p.unlink()
+			chroot_path.unlink()
diff --git a/archinstoo/archinstoo/lib/models/device.py b/archinstoo/archinstoo/lib/models/device.py
index ed811115..66150afa 100644
--- a/archinstoo/archinstoo/lib/models/device.py
+++ b/archinstoo/archinstoo/lib/models/device.py
@@ -835,8 +835,17 @@ def from_string(cls, s: str) -> Self | None:
 class PartitionGUID(Enum):
 	# A list of Partition type GUIDs (lsblk -o+PARTTYPE) can be found here: https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs
 
+	LINUX_ROOT_AARCH64 = 'B921B045-1DF0-41C3-AF44-4C6F280D3FAE'
 	LINUX_ROOT_X86_64 = '4F68BCE3-E8CD-4DB1-96E7-FBCAF984B709'
 
+	@classmethod
+	def linux_root(cls) -> Self:
+		# discoverable partitions spec keys root by arch: the wrong GUID
+		# leaves systemd-gpt-auto-generator unable to find /
+		if SysInfo.arch() == 'aarch64':
+			return cls.LINUX_ROOT_AARCH64
+		return cls.LINUX_ROOT_X86_64
+
 	@property
 	def bytes(self) -> builtins.bytes:
 		return uuid.UUID(self.value).bytes