-ifeq ($(LINUX_VERSION),)
- ifeq ($(KERNEL),2.4)
- LINUX_VERSION:=2.4.34
- LINUX_RELEASE:=1
- LINUX_KERNEL_MD5SUM:=f59665540a7f3351ea416a0dad104b55
- else
- LINUX_VERSION:=2.6.21.4
- LINUX_RELEASE:=1
- LINUX_KERNEL_MD5SUM:=c50995d713ba2d73f148e10073342568
- endif
-endif
-KERNEL:=2.$(word 2,$(subst ., ,$(strip $(LINUX_VERSION))))
+ifeq ($(KERNEL),2.4)
+ LINUX_VERSION?=2.4.37.4
+else
+ LINUX_VERSION?=2.6.21.7
+endif
+LINUX_RELEASE?=1
+
+ifeq ($(LINUX_VERSION),2.4.37.4)
+ LINUX_KERNEL_MD5SUM:=
+endif
+ifeq ($(LINUX_VERSION),2.6.21.7)
+ LINUX_KERNEL_MD5SUM:=bc15fad1487336d5dcb0945cd039d8ed
+endif
+ifeq ($(LINUX_VERSION),2.6.25.20)
+ LINUX_KERNEL_MD5SUM:=0da698edccf03e2235abc2830a495114
+endif
+ifeq ($(LINUX_VERSION),2.6.27.29)
+ LINUX_KERNEL_MD5SUM:=ab6991ee42603a4dbfba7956a54c89a4
+endif
+ifeq ($(LINUX_VERSION),2.6.28.10)
+ LINUX_KERNEL_MD5SUM:=c4efb2c494d749cb5de274f8ae41c3fa
+endif
+ifeq ($(LINUX_VERSION),2.6.30.4)
+ LINUX_KERNEL_MD5SUM:=ac05e32764368af7eff79c5e3df65efb
+endif
+
+# disable the md5sum check for unknown kernel versions
+LINUX_KERNEL_MD5SUM?=x
+
+split_version=$(subst ., ,$(1))
+merge_version=$(subst $(space),.,$(1))
+KERNEL_BASE=$(firstword $(subst -, ,$(LINUX_VERSION)))
+KERNEL=$(call merge_version,$(wordlist 1,2,$(call split_version,$(KERNEL_BASE))))
+KERNEL_PATCHVER=$(call merge_version,$(wordlist 1,3,$(call split_version,$(KERNEL_BASE))))