Adding a new hard drive to an Xbox 4GB model is fairly simple and the hard drives have instructions on how to do it. You just need to make sure you get the proper hard drive for your particular model (i.e. original design, S or E). Your internal 4GB flash
memory will still be active so you can either leave your information there or transfer it once you install the drive. Avoid 3rd party knock-off drives - they may be cheap but are typically not as good quality and will more than likely be missing the partition
that has the software which enables backwards compatibility with original Xbox games. Best to spend the extra money and get an official Microsoft hard drive.
In terms of the Xbox One, all you will be able to transfer is your gamer tag information, which you would download again. The Xbox One has no compatibility with 360 games so there is no need to transfer anything. None of your 360 games (physical or digital)
will work on the Xbox One. Some software add-ons will have your 360 purchase carry over to the One, like Pinball FX2 tables, Dance Central songs, and Rocksmith songs where you would just download them again from the marketplace as they will show as free, but
the vast majority of purchases do not carry over.
Did this solve your problem?
Sorry this didn't help.
Great! Thanks for marking this as the answer.
How satisfied are you with this reply?
Thanks for your feedback, it helps us improve the site.