diff --git a/nemu/Kconfig b/nemu/Kconfig
index adc8183..cd9b909 100644
--- a/nemu/Kconfig
+++ b/nemu/Kconfig
@@ -164,7 +164,7 @@ config MTRACE
 config MTRACE_RANGE
   depends on MTRACE
   string "Memory trace active range"
-  default "0-fffffff"
+  default "0-0xfffffff"
   help
     Memory tracer will only print memory access in these ranges.
     Use comma to seperate between ranges.
diff --git a/nemu/src/memory/paddr.c b/nemu/src/memory/paddr.c
index d34fec6..b694c85 100644
--- a/nemu/src/memory/paddr.c
+++ b/nemu/src/memory/paddr.c
@@ -69,7 +69,7 @@ void init_mem() {
   ptr = strtok_r(range, ",", &saveptr);
   for (range_count = 0; range_count < CONFIG_MTRACE_RANGE_MAX; ) {
     word_t start, end;
-    Assert(sscanf(ptr, FMT_WORD "-" FMT_WORD, &start, &end) == 2, "Config option MTRACE_RANGE has wrong format");
+    Assert(sscanf(ptr, FMT_PADDR "-" FMT_PADDR, &start, &end) == 2, "Config option MTRACE_RANGE has wrong format");
     mtrace_start[range_count] = start;
     mtrace_end[range_count] = end;