From 2e5eb135aac300032edd82e4b7a49a17dc80ba4d Mon Sep 17 00:00:00 2001
From: Samuel Dionne-Riel <samuel@dionne-riel.com>
Date: Tue, 27 Nov 2018 21:51:41 -0500
Subject: [PATCH] sd-image: Verifies the FAT partition before copying it.

This is to ensure `mtools`-based operations don't wreck the FS.
---
 nixos/modules/installer/cd-dvd/sd-image.nix | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/nixos/modules/installer/cd-dvd/sd-image.nix b/nixos/modules/installer/cd-dvd/sd-image.nix
index b6e1d11c2b54..e3b1ce3b7c42 100644
--- a/nixos/modules/installer/cd-dvd/sd-image.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image.nix
@@ -135,6 +135,8 @@ in
 
         # Copy the populated /boot into the SD image
         (cd boot; mcopy -bpsvm -i ../bootpart.img ./* ::)
+        # Verify the FAT partition before copying it.
+        fsck.vfat -vn bootpart.img
         dd conv=notrunc if=bootpart.img of=$img seek=$START count=$SECTORS
       '';
     }) {};