diff --git a/board/imgtec/boston/ddr.c b/board/imgtec/boston/ddr.c
index 8532225..cecf454 100644
--- a/board/imgtec/boston/ddr.c
+++ b/board/imgtec/boston/ddr.c
@@ -23,7 +23,7 @@
 	return 0;
 }
 
-phys_size_t board_get_usable_ram_top(phys_size_t total_size)
+phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
 {
 	DECLARE_GLOBAL_DATA_PTR;