diff --git a/conf/machine/raspberrypi.conf b/conf/machine/raspberrypi.conf
index 1e619a7..1b3702f 100644
--- a/conf/machine/raspberrypi.conf
+++ b/conf/machine/raspberrypi.conf
@@ -22,7 +22,7 @@ XSERVER = " \
 	xf86-video-fbdev \
 "
 
-KERNEL_IMAGETYPE = "Image"
+KERNEL_IMAGETYPE ?= "Image"
 
 MACHINE_FEATURES = "kernel26 apm usbhost keyboard vfat ext2 screen touchscreen alsa bluetooth wifi sdio"