diff --git a/devices/gl-ar750/default.nix b/devices/gl-ar750/default.nix
index 5f80509..d10337e 100644
--- a/devices/gl-ar750/default.nix
+++ b/devices/gl-ar750/default.nix
@@ -171,7 +171,6 @@
           AR8216_PHY = "y";         # eth1 is behind a switch
 
           MTD_SPI_NOR = "y";
-          MTD_SPI_NOR_USE_4K_SECTORS = "n";  # jffs2 needs min 8k erase block
 
           SPI_ATH79 = "y";      # these are copied from OpenWrt.
           SPI_MASTER= "y";      # At least one of them is necessary
diff --git a/devices/gl-mt300a/default.nix b/devices/gl-mt300a/default.nix
index 9c29af9..5cb71da 100644
--- a/devices/gl-mt300a/default.nix
+++ b/devices/gl-mt300a/default.nix
@@ -142,7 +142,6 @@
           MTD = "y";
           MTD_CMDLINE_PARTS = "y";
           MTD_BLOCK = "y";         # fix undefined ref to register_mtd_blktrans_devs
-          MTD_SPI_NOR_USE_4K_SECTORS = "n";
 
           CMDLINE_PARTITION = "y";
           EARLY_PRINTK = "y";
diff --git a/modules/flashimage.nix b/modules/flashimage.nix
index 085d7b2..2f68e2e 100644
--- a/modules/flashimage.nix
+++ b/modules/flashimage.nix
@@ -38,6 +38,8 @@ in {
     kernel = {
       config = {
         MTD_SPLIT_UIMAGE_FW = "y";
+        # https://stackoverflow.com/questions/26466470/can-the-logical-erase-block-size-of-an-mtd-device-be-increased
+        MTD_SPI_NOR_USE_4K_SECTORS = "n";
       };
     };