From 8cb2ce0f524a0aa4117b512e7b9953d4b67fcebc Mon Sep 17 00:00:00 2001
From: Samuel Dionne-Riel <samuel@dionne-riel.com>
Date: Sat, 22 May 2021 18:16:42 -0400
Subject: [PATCH] iso-image: Force gfxmode

https://www.gnu.org/software/grub/manual/grub/html_node/gfxmode.html
(cherry picked from commit f93f0e72e9ef423ed591951030f08cafd209e637)
---
 nixos/modules/installer/cd-dvd/iso-image.nix | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/nixos/modules/installer/cd-dvd/iso-image.nix b/nixos/modules/installer/cd-dvd/iso-image.nix
index 324b38070e4..3f5ac8a5113 100644
--- a/nixos/modules/installer/cd-dvd/iso-image.nix
+++ b/nixos/modules/installer/cd-dvd/iso-image.nix
@@ -185,6 +185,19 @@ let
     insmod gfxterm
     insmod png
     set gfxpayload=keep
+    set gfxmode=${concatStringsSep "," [
+      # GRUB will use the first valid mode listed here.
+      # `auto` will sometimes choose the smallest valid mode it detects.
+      # So instead we'll list a lot of possibly valid modes :/
+      #"3840x2160"
+      #"2560x1440"
+      "1920x1080"
+      "1366x768"
+      "1280x720"
+      "1024x768"
+      "800x600"
+      "auto"
+    ]}
 
     # Fonts can be loaded?
     # (This font is assumed to always be provided as a fallback by NixOS)