# How to create hybrid ISO images?



## vanessa (Nov 24, 2013)

I noticed that PC-BSD 10 preview comes in a new hybrid image format which can be written both to DVD and USB stick. Could someone enlighten me how to create such hybrid images myself under FreeBSD? After dd-ing the image to a USB stick, gpart reveals a GPT partitioning scheme with just one freebsd-boot partition and unallocated space:


```
# gpart show da0
=>      34  31268797  da0  GPT  (15G) [CORRUPT]
        34       128    1  freebsd-boot  (64K)
       162  31268669       - free -  (15G)
```

But which boot code is used to boot off the raw space and how does the whole work? 

PC-BSD automatically detects and mounts the volume. What is the logic behind this and how could I mount it manually under FreeBSD if no partition exists?


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