diff --git a/overlay.nix b/overlay.nix
index c1fb5f0..7a4eb27 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -22,8 +22,9 @@ final: prev:
   qemu = prev.qemu.override { rutabagaSupport = false; };
 
   uboot-custom = prev.ubootQemuRiscv64Smode.override {
+    # Override preboot to set 'bootcmd' directly to the kernel address in RAM
     extraConfig = ''
-      CONFIG_CMD_QFW=y
+      CONFIG_PREBOOT="setenv fdt_addr ''${fdtcontroladdr}; fdt addr ''${fdtcontroladdr}; setenv bootcmd booti ''${kernel_addr_r} - ''${fdtcontroladdr};"
     '';
   };