Attach a specially crafted disk image with gpart(modified kernel to support creating large GPT entry numbers):
```
root@:~ # truncate -s 64M test.img
root@:~ # mdconfig test.img
md0
root@:~ # gpart create -s GPT -n 8192 md0
md0 created
root@:~ # mdconfig -du 0
```
Reattach the disk image.
```
root@:~ # mdconfig test.img
GEOM: md0: unsupported GPT detected.
GEOM: md0: GPT entry number: 8192, entry size: 128.
GEOM: md0: maximum supported GPT entry number: 4096, entry size: 1024.
GEOM: md0: GPT rejected.
```