How to edit files in an image without deploying...

[Keith Gregory]

I like your idea of booting into a pre-boot environment to do minor changes; however it seems like you are taking are hard approach at doing this when you could be creating your image with virtual box using snapshots at each major step so if you miss something or mess something up you can just revert the snapshot. Its still a timely and daunting process to create an image this way but it takes out the headaches of having to start from scratch each time. Then each time you think you have it right or after each modification you simply upload your new image over your old one.