diff --git a/include/logger.h b/include/logger.h
index 3cec69d..f472760 100644
--- a/include/logger.h
+++ b/include/logger.h
@@ -101,11 +101,11 @@ logger_cur = _Generic((msg), \
 // #define DEBUG_DTB(val) DEBUG(val)
 #define DEBUG_DTB(val) CLEAN
 
-#define DEBUG_EXCEP(val) DEBUG(val)
-// #define DEBUG_EXCEP(val) CLEAN
+// #define DEBUG_EXCEP(val) DEBUG(val)
+#define DEBUG_EXCEP(val) CLEAN
 
-// #define DEBUG_MEM(val) DEBUG(val)
-#define DEBUG_MEM(val) CLEAN
+#define DEBUG_MEM(val) DEBUG(val)
+// #define DEBUG_MEM(val) CLEAN
 
 // #define DEBUG_INITRD(val) DEBUG(val)
 #define DEBUG_INITRD(val) CLEAN
diff --git a/kernel/lib/uart.c b/kernel/lib/uart.c
index aa5a6b9..369275d 100644
--- a/kernel/lib/uart.c
+++ b/kernel/lib/uart.c
@@ -209,11 +209,10 @@ void uart_puts(const char *s)
 void uart_hex(uint64_t d)
 {
   char buf[0x11], *p = buf;
-  uint64_t n;
-  for (int c = 28; c >= 0; c -= 4) {
+  for (int c = 28, n; c >= 0; c -= 4) {
     n = (d >> c) & 0xf;
-    n += n > 9 ? (char)'A' : (char)'0';
-    *p++ = n;
+    n += (n > 9) ? 0x37 : 0x30;
+    *p++ = (char)n;
   }
   *p = '\0';
   uart_puts(buf);