diff --git a/hw/ipmi/isa_ipmi_bt.c b/hw/ipmi/isa_ipmi_bt.c
index e946030e84..8bbb1fa785 100644
--- a/hw/ipmi/isa_ipmi_bt.c
+++ b/hw/ipmi/isa_ipmi_bt.c
@@ -22,6 +22,7 @@
  * THE SOFTWARE.
  */
 #include "qemu/osdep.h"
+#include "qemu/log.h"
 #include "qapi/error.h"
 #include "hw/hw.h"
 #include "hw/ipmi/ipmi.h"
@@ -450,22 +451,63 @@ static void isa_ipmi_bt_realize(DeviceState *dev, Error **errp)
     isa_register_ioport(isadev, &iib->bt.io, iib->bt.io_base);
 }
 
-static const VMStateDescription vmstate_ISAIPMIBTDevice = {
-    .name = TYPE_IPMI_INTERFACE,
+static int ipmi_bt_vmstate_post_load(void *opaque, int version)
+{
+    IPMIBT *ib = opaque;
+
+    /* Make sure all the values are sane. */
+    if (ib->outpos >= MAX_IPMI_MSG_SIZE || ib->outlen >= MAX_IPMI_MSG_SIZE ||
+        ib->outpos >= ib->outlen) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "ipmi:bt: vmstate transfer received bad out values: %d %d\n",
+                      ib->outpos, ib->outlen);
+        ib->outpos = 0;
+        ib->outlen = 0;
+    }
+
+    if (ib->inlen >= MAX_IPMI_MSG_SIZE) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "ipmi:bt: vmstate transfer received bad in value: %d\n",
+                      ib->inlen);
+        ib->inlen = 0;
+    }
+
+    return 0;
+}
+
+const VMStateDescription vmstate_IPMIBT = {
+    .name = TYPE_IPMI_INTERFACE_PREFIX "bt",
     .version_id = 1,
     .minimum_version_id = 1,
+    .post_load = ipmi_bt_vmstate_post_load,
     .fields      = (VMStateField[]) {
-        VMSTATE_BOOL(bt.obf_irq_set, ISAIPMIBTDevice),
-        VMSTATE_BOOL(bt.atn_irq_set, ISAIPMIBTDevice),
-        VMSTATE_BOOL(bt.use_irq, ISAIPMIBTDevice),
-        VMSTATE_BOOL(bt.irqs_enabled, ISAIPMIBTDevice),
-        VMSTATE_UINT32(bt.outpos, ISAIPMIBTDevice),
-        VMSTATE_VBUFFER_UINT32(bt.outmsg, ISAIPMIBTDevice, 1, NULL, bt.outlen),
-        VMSTATE_VBUFFER_UINT32(bt.inmsg, ISAIPMIBTDevice, 1, NULL, bt.inlen),
-        VMSTATE_UINT8(bt.control_reg, ISAIPMIBTDevice),
-        VMSTATE_UINT8(bt.mask_reg, ISAIPMIBTDevice),
-        VMSTATE_UINT8(bt.waiting_rsp, ISAIPMIBTDevice),
-        VMSTATE_UINT8(bt.waiting_seq, ISAIPMIBTDevice),
+        VMSTATE_BOOL(obf_irq_set, IPMIBT),
+        VMSTATE_BOOL(atn_irq_set, IPMIBT),
+        VMSTATE_BOOL(irqs_enabled, IPMIBT),
+        VMSTATE_UINT32(outpos, IPMIBT),
+        VMSTATE_UINT32(outlen, IPMIBT),
+        VMSTATE_UINT8_ARRAY(outmsg, IPMIBT, MAX_IPMI_MSG_SIZE),
+        VMSTATE_UINT32(inlen, IPMIBT),
+        VMSTATE_UINT8_ARRAY(inmsg, IPMIBT, MAX_IPMI_MSG_SIZE),
+        VMSTATE_UINT8(control_reg, IPMIBT),
+        VMSTATE_UINT8(mask_reg, IPMIBT),
+        VMSTATE_UINT8(waiting_rsp, IPMIBT),
+        VMSTATE_UINT8(waiting_seq, IPMIBT),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_ISAIPMIBTDevice = {
+    .name = TYPE_IPMI_INTERFACE_PREFIX "isa-bt",
+    .version_id = 2,
+    .minimum_version_id = 2,
+    /*
+     * Version 1 had messed up the array transfer, it's not even usable
+     * because it used VMSTATE_VBUFFER_UINT32, but it did not transfer
+     * the buffer length, so random things would happen.
+     */
+    .fields      = (VMStateField[]) {
+        VMSTATE_STRUCT(bt, ISAIPMIBTDevice, 1, vmstate_IPMIBT, IPMIBT),
         VMSTATE_END_OF_LIST()
     }
 };