diff --git a/hw/fdc.c b/hw/fdc.c
index db57710..d761e62 100644
--- a/hw/fdc.c
+++ b/hw/fdc.c
@@ -1871,14 +1871,14 @@
     }
 }
 
-fdctrl_t *fdctrl_init_isa(int isairq, int dma_chann,
-                          uint32_t io_base,
-                          BlockDriverState **fds)
+fdctrl_t *fdctrl_init_isa(BlockDriverState **fds)
 {
     fdctrl_t *fdctrl;
     ISADevice *dev;
+    int isairq = 6;
+    int dma_chann = 2;
 
-    dev = isa_create_simple("isa-fdc", io_base, 0, isairq, -1);
+    dev = isa_create_simple("isa-fdc", isairq, -1);
     fdctrl = &(DO_UPCAST(fdctrl_isabus_t, busdev, dev)->state);
 
     fdctrl->dma_chann = dma_chann;
@@ -1968,14 +1968,15 @@
 {
     fdctrl_isabus_t *isa = DO_UPCAST(fdctrl_isabus_t, busdev, dev);
     fdctrl_t *fdctrl = &isa->state;
+    int iobase = 0x3f0;
 
-    register_ioport_read(isa->busdev.iobase[0] + 0x01, 5, 1,
+    register_ioport_read(iobase + 0x01, 5, 1,
                          &fdctrl_read_port, fdctrl);
-    register_ioport_read(isa->busdev.iobase[0] + 0x07, 1, 1,
+    register_ioport_read(iobase + 0x07, 1, 1,
                          &fdctrl_read_port, fdctrl);
-    register_ioport_write(isa->busdev.iobase[0] + 0x01, 5, 1,
+    register_ioport_write(iobase + 0x01, 5, 1,
                           &fdctrl_write_port, fdctrl);
-    register_ioport_write(isa->busdev.iobase[0] + 0x07, 1, 1,
+    register_ioport_write(iobase + 0x07, 1, 1,
                           &fdctrl_write_port, fdctrl);
     isa_init_irq(&isa->busdev, &fdctrl->irq);