diff --git a/buildroot-external/rootfs-overlay/usr/lib/systemd/system/haos-expand.service b/buildroot-external/rootfs-overlay/usr/lib/systemd/system/haos-expand.service
index 965ce98d2..0e3c95884 100644
--- a/buildroot-external/rootfs-overlay/usr/lib/systemd/system/haos-expand.service
+++ b/buildroot-external/rootfs-overlay/usr/lib/systemd/system/haos-expand.service
@@ -9,6 +9,11 @@ After=dev-disk-by\x2dlabel-hassos\x2ddata.device systemd-fsck@dev-disk-by\x2dlab
 
 [Service]
 Type=oneshot
+# Resizing the data partition can take a long time on slow or previously used
+# disks. There is no point in aborting it after the default start timeout: if
+# the resize fails the system is unusable anyway, so let it run for as long as
+# it needs instead of failing the boot. See #3365.
+TimeoutStartSec=infinity
 ExecStart=/usr/libexec/haos-expand
 
 [Install]