diff --git a/kernel/config.c b/kernel/config.c
index 4643a6d..5602da6 100644
--- a/kernel/config.c
+++ b/kernel/config.c
@@ -62,7 +62,7 @@ STATIC struct MenuSelector MenuStruct[MENULINESMAX] BSS_INIT({0});
 
 int nMenuLine BSS_INIT(0);
 int MenuColor = -1;
-extern UBYTE kernel_command_line[256];
+extern char kernel_command_line[256];
 extern int kernel_command_line_length;
 
 STATIC void WriteMenuLine(struct MenuSelector *menu)
@@ -866,9 +866,9 @@ VOID DoConfig(int nPass)
     unsigned ii;
     static char commandbuffer[256];
     char * end = &kernel_command_line[kernel_command_line_length];
-    char * configfile = "";
-    char * altconfigfile = "fdconfig.sys";
-    char * oldconfigfile = "config.sys";
+    static char * configfile = "";
+    static char * altconfigfile = "fdconfig.sys";
+    static char * oldconfigfile = "config.sys";
     struct { char ** pointer; char const * command; }
       configcommands[] = {
         { &configfile, "CONFIG" },
diff --git a/kernel/main.c b/kernel/main.c
index ea06803..b84de3c 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -68,8 +68,8 @@ __segment DosTextSeg = 0;
 
 struct lol FAR *LoL = &DATASTART;
 
-struct _KernelConfig InitKernelConfig = { 0xFF };
-UBYTE kernel_command_line[256] = { 0x00, 0xFF }; /* special none value */
+struct _KernelConfig InitKernelConfig = { -1 };
+char kernel_command_line[256] = { 0, -1 }; /* special none value */
 int kernel_command_line_length BSS_INIT(0);
 UBYTE debugger_present = 0xFF;	/* initialised in kernel.asm
 				   do NOT set 0 here or compiler may
@@ -111,7 +111,7 @@ VOID ASMCFUNC FreeDOSmain(void)
 
 #ifdef DEBUG
   /* printf must go after setup_int_vectors call */
-  if (kernel_command_line[0] == 0x00 && kernel_command_line[1] == 0xFF) {
+  if (kernel_command_line[0] == 0 && kernel_command_line[1] == (char)-1) {
     printf("\nKERNEL: Command line is not specified.\n");
   } else {
     printf("\nKERNEL: Command line is \"%s\"\n", kernel_command_line);