diff --git a/src/sio/sio_pc87309.c b/src/sio/sio_pc87309.c
index 2219ede17..5e417aefb 100644
--- a/src/sio/sio_pc87309.c
+++ b/src/sio/sio_pc87309.c
@@ -116,12 +116,16 @@ superio_handler(pc87309_t *dev)
     io_removehandler(0x02e, 0x0002,
                      pc87309_read, NULL, NULL, pc87309_write, NULL, NULL, dev);
 
-    switch (dev->baddr) {
-        case 2:
+    switch (dev->regs[0x21] & 0x0b) {
+        case 0x02:
+        case 0x08:
+        case 0x0a:
             io_sethandler(0x15c, 0x0002,
                           pc87309_read, NULL, NULL, pc87309_write, NULL, NULL, dev);
             break;
-        case 3:
+        case 0x03:
+        case 0x09:
+        case 0x0b:
             io_sethandler(0x02e, 0x0002,
                           pc87309_read, NULL, NULL, pc87309_write, NULL, NULL, dev);
             break;
@@ -218,10 +222,10 @@ pc87309_write(uint16_t port, uint8_t val, void *priv)
             case 0x07:
             case 0x21:
                 dev->regs[dev->cur_reg] = val;
+                superio_handler(dev);
                 break;
             case 0x22:
                 dev->regs[dev->cur_reg] = val & 0x7f;
-                superio_handler(dev);
                 break;
             default:
                 if (dev->cur_reg >= 0x30) {
@@ -403,8 +407,7 @@ pc87309_reset(pc87309_t *dev)
     memset(dev->pm, 0x00, 0x08);
 
     dev->regs[0x20] = dev->id;
-    dev->regs[0x21] = 0x04;
-    dev->regs[0x22] = dev->baddr;
+    dev->regs[0x21] = 0x04 | dev->baddr;
 
     dev->ld_regs[0x00][0x01] = 0x01;
     dev->ld_regs[0x00][0x30] = 0x03;
@@ -500,7 +503,7 @@ pc87309_init(const device_t *info)
 
     dev->fdc = device_add(&fdc_at_nsc_device);
 
-    dev->baddr = (info->local & 0x100) ? 2 : 3;
+    dev->baddr = (info->local & 0x100) ? 8 : 9;
 
     pc87309_reset(dev);