Extend validate_bootloader_layout with UEFI-dependent checks

Add is_uefi parameter and three new validations: Systemd-boot, Efistub
and rEFInd require UEFI; Efistub additionally requires a FAT boot
partition. Move the rEFInd UEFI-only check out of GlobalMenu so
guided.py and Installer silent-install paths get the same coverage.

archinstall/lib/bootloader/utils.py

@@ -9,6 +9,8 @@ from archinstall.lib.models.device import DiskLayoutConfiguration
 class BootloaderValidationFailureKind(Enum):
 	LimineNonFatBoot = auto()
 	LimineLayout = auto()
+	BootloaderRequiresUefi = auto()
+	EfistubNonFatBoot = auto()
 
 
 @dataclass(frozen=True)
@@ -17,9 +19,13 @@ class BootloaderValidationFailure:
 	description: str
 
 
+_UEFI_ONLY_BOOTLOADERS = (Bootloader.Systemd, Bootloader.Efistub, Bootloader.Refind)
+
+
 def validate_bootloader_layout(
 	bootloader_config: BootloaderConfiguration | None,
 	disk_config: DiskLayoutConfiguration | None,
+	is_uefi: bool,
 ) -> BootloaderValidationFailure | None:
 	"""Validate bootloader configuration against disk layout.
 
@@ -29,12 +35,32 @@ def validate_bootloader_layout(
 	if not (bootloader_config and disk_config):
 		return None
 
-	if bootloader_config.bootloader == Bootloader.Limine:
-		boot_part = next(
-			(p for m in disk_config.device_modifications if (p := m.get_boot_partition())),
-			None,
+	bootloader = bootloader_config.bootloader
+
+	if bootloader == Bootloader.NO_BOOTLOADER:
+		return None
+
+	if bootloader in _UEFI_ONLY_BOOTLOADERS and not is_uefi:
+		return BootloaderValidationFailure(
+			kind=BootloaderValidationFailureKind.BootloaderRequiresUefi,
+			description=f'{bootloader.value} requires a UEFI system.',
 		)
 
+	boot_part = next(
+		(p for m in disk_config.device_modifications if (p := m.get_boot_partition())),
+		None,
+	)
+
+	if bootloader == Bootloader.Efistub:
+		# The UEFI firmware reads the kernel directly from the boot partition,
+		# which must be FAT.
+		if boot_part and (boot_part.fs_type is None or not boot_part.fs_type.is_fat()):
+			return BootloaderValidationFailure(
+				kind=BootloaderValidationFailureKind.EfistubNonFatBoot,
+				description='Efistub does not support booting with a non-FAT boot partition.',
+			)
+
+	if bootloader == Bootloader.Limine:
 		# Limine reads its config and kernels from the boot partition, which
 		# must be FAT.
 		if boot_part and (boot_part.fs_type is None or not boot_part.fs_type.is_fat()):

archinstall/lib/global_menu.py

@@ -461,8 +461,6 @@ class GlobalMenu(AbstractMenu[None]):
 		if not bootloader_config or bootloader_config.bootloader == Bootloader.NO_BOOTLOADER:
 			return None
 
-		bootloader = bootloader_config.bootloader
-
 		if disk_config := self._item_group.find_by_key('disk_config').value:
 			for layout in disk_config.device_modifications:
 				if root_partition := layout.get_root_partition():
@@ -490,10 +488,7 @@ class GlobalMenu(AbstractMenu[None]):
 			if efi_partition.fs_type is None or not efi_partition.fs_type.is_fat():
 				return 'ESP must be formatted as a FAT filesystem'
 
-		if bootloader == Bootloader.Refind and not self._uefi:
-			return 'rEFInd can only be used on UEFI systems'
-
-		if failure := validate_bootloader_layout(bootloader_config, disk_config):
+		if failure := validate_bootloader_layout(bootloader_config, disk_config, self._uefi):
 			return failure.description
 
 		return None

archinstall/lib/installer.py

@@ -1472,6 +1472,7 @@ class Installer:
 			if failure := validate_bootloader_layout(
 				BootloaderConfiguration(bootloader=Bootloader.Limine, uki=uki_enabled),
 				self._disk_config,
+				SysInfo.has_uefi(),
 			):
 				raise DiskError(failure.description)
 

archinstall/scripts/guided.py

@@ -11,6 +11,7 @@ from archinstall.lib.disk.filesystem import FilesystemHandler
 from archinstall.lib.disk.utils import disk_layouts
 from archinstall.lib.general.general_menu import PostInstallationAction, select_post_installation
 from archinstall.lib.global_menu import GlobalMenu
+from archinstall.lib.hardware import SysInfo
 from archinstall.lib.installer import Installer, accessibility_tools_in_use, run_custom_user_commands
 from archinstall.lib.menu.util import delayed_warning
 from archinstall.lib.mirror.mirror_handler import MirrorListHandler
@@ -217,6 +218,7 @@ def main(arch_config_handler: ArchConfigHandler | None = None) -> None:
 	if failure := validate_bootloader_layout(
 		arch_config_handler.config.bootloader_config,
 		arch_config_handler.config.disk_config,
+		SysInfo.has_uefi(),
 	):
 		error(failure.description)
 		return