diff --git a/kernel/ping.c b/kernel/ping.c
index 180b4420..09a382bf 100644
--- a/kernel/ping.c
+++ b/kernel/ping.c
@@ -99,7 +99,7 @@ static u32_t ping_time;
 /* port-defined functions used for timer execution */
 //void sys_msleep(u32_t ms);
 
-static u32_t sys_now() 
+inline u32_t sys_now(void) 
 {
 	static uint64_t start = 0;
 	uint64_t end;
diff --git a/lwip/src/include/arch/cc.h b/lwip/src/include/arch/cc.h
index 97c69292..d7f3e8d8 100644
--- a/lwip/src/include/arch/cc.h
+++ b/lwip/src/include/arch/cc.h
@@ -69,6 +69,8 @@ typedef size_t mem_ptr_t;
 #define MEM_ALIGNMENT 4
 #define ETH_PAD_SIZE  2
 
+#define LWIP_CHKSUM_ALGORITHM 2
+
 /* prototypes for printf() and abort() */
 #include <metalsvm/stdio.h>
 #include <metalsvm/stdlib.h>