The compactflash image contains 3 partition:
– /dev/hda1 is the /boot that contains the kernel and the initrd images and therefore is mounted in readolny mode;
– /dev/hda2 contains the livecd iso image and therefore is readonly;
– the last partition contains the database for the configuration and it is a RW partition. I have been using this type of device for 2 years (the same compactflash) and I never had a problem. In any case you can store the database on a hard disk if you prefer.