diff --git a/debian/changelog b/debian/changelog
index 72a5c592e..c645e3bbd 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+grub2 (2.06-5) UNRELEASED; urgency=high
+
+  [ Steve McIntyre ]
+  * Explicitly unset SOURCE_DATE_EPOCH before running fs tests
+
+ -- Steve McIntyre <93sam@debian.org>  Wed, 14 Sep 2022 22:35:49 +0100
+
 grub2 (2.06-4) unstable; urgency=high
 
   [ Steve McIntyre ]
diff --git a/debian/patches/fs-tester-time-fail.patch b/debian/patches/fs-tester-time-fail.patch
new file mode 100644
index 000000000..43675db6f
--- /dev/null
+++ b/debian/patches/fs-tester-time-fail.patch
@@ -0,0 +1,27 @@
+Explicitly unset SOURCE_DATE_EPOCH before running fs tests. In some
+filesystem utils like mksquashfs, it will silently change behaviour
+and cause timestamps to unexpectedly change. Reproducible builds are
+good and useful for shipped artifacts, but this causes build-time
+tests to fail.
+
+Author: Steve McIntyre
+
+Patch-Name: fs-tester-time-fail.patch
+---
+ tests/util/grub-fs-tester.in | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/tests/util/grub-fs-tester.in b/tests/util/grub-fs-tester.in
+index bfc425e1f..660691302 100644
+--- a/tests/util/grub-fs-tester.in
++++ b/tests/util/grub-fs-tester.in
+@@ -4,6 +4,9 @@ set -e
+ 
+ fs="$1"
+ 
++# We can't have this set, or filesystem tests will fail
++unset SOURCE_DATE_EPOCH
++
+ GRUBFSTEST="@builddir@/grub-fstest"
+ 
+ tempdir=`mktemp -d "${TMPDIR:-/tmp}/tmp.XXXXXXXXXX"` || exit 1
diff --git a/debian/patches/series b/debian/patches/series
index 66a1bd404..48389f862 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -90,3 +90,4 @@ minilzo-2.10.patch
 0090-fs-btrfs-Fix-several-fuzz-issues-with-invalid-dir-it.patch
 0091-fs-btrfs-Fix-more-ASAN-and-SEGV-issues-found-with-fu.patch
 0092-fs-btrfs-Fix-more-fuzz-issues-related-to-chunks.patch
+fs-tester-time-fail.patch
diff --git a/tests/util/grub-fs-tester.in b/tests/util/grub-fs-tester.in
index bfc425e1f..660691302 100644
--- a/tests/util/grub-fs-tester.in
+++ b/tests/util/grub-fs-tester.in
@@ -4,6 +4,9 @@ set -e
 
 fs="$1"
 
+# We can't have this set, or filesystem tests will fail
+unset SOURCE_DATE_EPOCH
+
 GRUBFSTEST="@builddir@/grub-fstest"
 
 tempdir=`mktemp -d "${TMPDIR:-/tmp}/tmp.XXXXXXXXXX"` || exit 1