From 77d3722c1580dc25219f590754e2e6bf34441e99 Mon Sep 17 00:00:00 2001
From: Tim Keller <tjk@tjkeller.xyz>
Date: Sat, 3 Jan 2026 17:53:34 -0600
Subject: zfs support in bootloader

---
 nixos/bootloader.nix | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/nixos/bootloader.nix b/nixos/bootloader.nix
index bb807cf..e2921bf 100644
--- a/nixos/bootloader.nix
+++ b/nixos/bootloader.nix
@@ -1,7 +1,5 @@
 { lib, config, ... }: let
 	cfg = config.boot._loader;
-	usingEfi  = cfg.mode == "efi";
-	usingBios = cfg.mode == "bios";
 in {
 	options.boot._loader = {
 		enable = lib.mkEnableOption "enable unified bootloader config";
@@ -20,17 +18,36 @@ in {
 				type = lib.types.str;
 				description = "device to install grub on";
 			};
+			zfsSupport = lib.mkEnableOption "zfs boot device support";
 		};
 		memtest86.enable = lib.mkEnableOption "make Memtest86+ available from the bootloader";
 	};
 
-	config = lib.mkIf cfg.enable {
+	config = let
+		usingEfi  = cfg.mode == "efi";
+		usingBios = cfg.mode == "bios";
+	in lib.mkIf cfg.enable {
+		assertions = [
+			{
+				assertion = cfg.loader != "grub" || !cfg.grub.zfsSupport || usingEfi;
+				message = "zfsSupport option requires using efi boot mode";
+			}
+		];
+
 		boot.loader = {
 			grub = lib.mkIf (cfg.loader == "grub") {
 				enable = true;
+				# bios
+				device = lib.mkIf usingBios cfg.grub.biosDevice;
+				# efi
 				efiSupport = usingEfi;
 				efiInstallAsRemovable = usingEfi;
-				device = if usingBios then cfg.grub.biosDevice else "nodev";
+				# zfs
+				zfsSupport = cfg.grub.zfsSupport;
+				mirroredBoots = lib.mkIf cfg.grub.zfsSupport [
+					{ devices = [ "nodev" ]; path = "/boot"; }
+				];
+				# misc
 				enableCryptodisk = true;
 				memtest86.enable = cfg.memtest86.enable;
 			};
-- 
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