I have something to add to this. I'm not sure if it's been said or not, did a simple search and didn't find this listed in the thread.
Sony's attempt to kill used game sales is tied to your PSN account, not your system. I sent my Vita in because of a button not being responsive, and unlocked trophies just fine on two separate games (MGS2HD, Zen Pinball 2) that I had saves for before sending my Vita in.
For those who don't know (I'm sure it's mentioned in this thread) to prevent used game sales, Sony locks trophies when you try and play a game in a different system than the one you originally used. This is, in reality, tied to your PSN account, not your Vita. I did not have to erase my saves to earn trophies in any of the games I've played before and after sending my Vita in for repair.
To delete apps and change your wallpaper hold on the touchscreen for apps press the ... Button after you have held the home screen long enough. for wallpaper after you have held the home screen, press the rectangular button on the lower right then choose select photo.
-PSN:GenjiXGlove- --The toothbrush has to be the greatest invention of all time.--