diff --git a/src/chipset/cs8220.c b/src/chipset/cs8220.c
index 3c3c23767..d66ac5246 100644
--- a/src/chipset/cs8220.c
+++ b/src/chipset/cs8220.c
@@ -242,9 +242,13 @@ cs8220_init(UNUSED(const device_t *info))
             dev->ram_banks[0].virt = 0x00000000;
             dev->ram_banks[0].phys = 0x00000000;
             dev->ram_banks[0].size = 0x00080000;
-            dev->ram_banks[1].virt = 0x00100000;
+            dev->ram_banks[1].virt = 0x00080000;
             dev->ram_banks[1].phys = 0x00080000;
-            dev->ram_banks[1].size = 0x00080000;
+            dev->ram_banks[1].size = 0x00020000;
+            /* Pretend there's a 384k expansion. */
+            dev->ram_banks[2].virt = 0x00100000;
+            dev->ram_banks[2].phys = 0x00080000;
+            dev->ram_banks[2].size = 0x00060000;
             break;
     }