# Use the default kernel version if the Makefile doesn't override it
-ifeq ($(LINUX_VERSION),)
- ifeq ($(KERNEL),2.4)
- LINUX_VERSION:=2.4.34
- LINUX_RELEASE:=1
- LINUX_KERNEL_MD5SUM:=f59665540a7f3351ea416a0dad104b55
- else
- LINUX_VERSION:=2.6.21.1
- LINUX_RELEASE:=1
- LINUX_KERNEL_MD5SUM:=a28b78793cd368592f7873bf36cb38b0
- endif
-endif
-KERNEL:=2.$(word 2,$(subst ., ,$(strip $(LINUX_VERSION))))
+ifeq ($(KERNEL),2.4)
+ LINUX_VERSION?=2.4.34
+else
+ LINUX_VERSION?=2.6.21.5
+endif
+LINUX_RELEASE?=1
+
+ifeq ($(LINUX_VERSION),2.4.34)
+ LINUX_KERNEL_MD5SUM:=f59665540a7f3351ea416a0dad104b55
+endif
+ifeq ($(LINUX_VERSION),2.6.22.4)
+ LINUX_KERNEL_MD5SUM:=6cf83acf21e65dcea4a5170c0bbc7125
+endif
+ifeq ($(LINUX_VERSION),2.6.21.5)
+ LINUX_KERNEL_MD5SUM:=2e9a302b5d514b231640227d6a2ab7bf
+endif
+ifeq ($(LINUX_VERSION),2.6.23)
+ LINUX_KERNEL_MD5SUM:=2cc2fd4d521dc5d7cfce0d8a9d1b3472
+endif
+
+# disable the md5sum check for unknown kernel versions
+LINUX_KERNEL_MD5SUM?=x
+
+KERNEL?=2.$(word 2,$(subst ., ,$(strip $(LINUX_VERSION))))
+KERNEL_PATCHVER=$(shell echo '$(LINUX_VERSION)' | cut -d. -f1,2,3 | cut -d- -f1)