diff --git a/include/rp6502.h b/include/rp6502.h
index cff43ff66..2c0e78b87 100644
--- a/include/rp6502.h
+++ b/include/rp6502.h
@@ -166,7 +166,7 @@ int __fastcall__ f_chmod (const char* path, unsigned char attr, unsigned char ma
 int __fastcall__ f_utime (const char* path, unsigned fdate, unsigned ftime, unsigned crdate, unsigned crtime);
 int __fastcall__ f_mkdir (const char* name);
 int __fastcall__ f_chdrive (const char* name);
-int __fastcall__ f_getcwd (char* name, unsigned len);
+int __fastcall__ f_getcwd (char* name, int size);
 int __fastcall__ f_setlabel (const char* name);
 int __fastcall__ f_getlabel (const char* path, char* label);
 int __fastcall__ f_getfree (const char* name, unsigned long* free, unsigned long* total);
diff --git a/libsrc/rp6502/f_getcwd.c b/libsrc/rp6502/f_getcwd.c
index 477474cbf..ef9a0ef22 100644
--- a/libsrc/rp6502/f_getcwd.c
+++ b/libsrc/rp6502/f_getcwd.c
@@ -2,10 +2,10 @@
 #include <errno.h>
 #include <string.h>
 
-int __fastcall__ f_getcwd (char* name, unsigned len)
+int __fastcall__ f_getcwd (char* name, int size)
 {
     int i, ax;
-    ria_set_ax (len);
+    ria_set_ax (size);
     ax = ria_call_int (RIA_OP_GETCWD);
     for (i = 0; i < ax; i++) {
         name[i] = ria_pop_char ();