diff --git a/doc/c64.sgml b/doc/c64.sgml
index 98008ef41..96260b48e 100644
--- a/doc/c64.sgml
+++ b/doc/c64.sgml
@@ -5,7 +5,7 @@
 <title>Commodore 64-specific information for cc65
 <author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz"><newline>
 <url url="mailto:greg.king5@verizon.net" name="Greg King">
-<date>2017-01-18
+<date>2018-05-14
 
 <abstract>
 An overview over the C64 runtime system as it is implemented for the cc65 C
@@ -122,8 +122,8 @@ since the program must be loaded to the BASIC start address.
 <sect1>80 Columns conio driver<p>
 
 The C64 package comes with an alternative software driven 80 columns
-module <tt/c64-soft80.o/ which uses the memory under I/O between &dollar;d000
-and &dollar;ffff.
+module <tt/c64-soft80.o/ which uses the memory under I/O between &dollar;D000
+and &dollar;FF3F.
 
 In memory constrained situations the memory from &dollar;400 to &dollar;7FF
 can be made available to a program by calling <tt/_heapadd ((void *) 0x0400, 0x0400);/