diff --git a/src/cs8230.c b/src/cs8230.c
index 783c179..c2125ed 100644
--- a/src/cs8230.c
+++ b/src/cs8230.c
@@ -112,4 +112,9 @@ void cs8230_init(void)
                         cs8230_read, NULL, NULL,
                         cs8230_write, NULL, NULL,
                         NULL);
+	if (mem_size > 768)
+        {
+                mem_mapping_set_addr(&ram_mid_mapping, 0xa0000, mem_size > 1024 ? 0x60000 : 0x20000 + (mem_size - 768) * 1024);
+                mem_mapping_set_exec(&ram_mid_mapping, ram + 0xa0000);
+        }
 }