Your boss probably knows that this is new tech for you, and that your results take longer and are less robust. As you say in your comment, the real experts are just too busy – you’re all he’s got. Thus, don’t assume that you are performing below expectations, because you’re not expected to have mastered the technology.

Your boss might also think that the best way for you to master the technology is to dive head-first into it. A lot of people don’t realize that other people think differently, and learn differently! It’s up to you to let your boss know that you think a different way would be more effective.

And if I chose to stay, I’d talk with my manager about why the hours of 8:00-4:30 were important enough to make them part of the job posting, and how I was going to move the new employee back to those hours. (This all assumes that coverage of those hours wasn’t arbitrary and that adherence really was important).

I would then inform the upcoming employee of the work hours I expected to be covered, and I’d prepare for the scenario where the new employee chose to not come aboard after all.

I view backing up middle-managers (at least publicly) as vitally important in a workplace. I wouldn’t work for a company where I was expecting my decisions to be undermined on a regular basis.

Some good answers here, let me add:

I would definitely NOT apply and then try to avoid having your friend see you when you show up for the interview, like trying to schedule an interview when he’s out of town. Surely if you get the job, he’s going to find out sooner or later, and at that point it will be far more awkward than it would be if you told him up front.

I’ve had two times I’ve gotten involved in new business start-ups by friends, and both times it ended badly. Not horrible, we were screaming at each other, friendship ruined forever badly, but things didn’t work out, I wanted out of this deal but now it’s awkward badly. Any time something like this comes up, I find myself thinking, If this doesn’t work out for whatever reason, is it going to ruin our friendship? And do I value the job or whatever the deal is more than I value the friendship?

To expand a bit on my comment on @KateGregory’s answer, the problem you face with using your own computer is “who owns what?”. How is a line drawn between things that you do on that computer for the company vs. for yourself? If you work on other projects off the clock, can the company make any claim to those? Does the computer have to comply with all corporate standards & policies, including antivirus, web filtering, remote scanning for unapproved software, etc.? Who owns the software you’re using? Who’s responsible for the licensing?

You are going to have to wait a couple weeks before you can make any kind of pitch to get a usable computer. Otherwise, you come across as the new guy who wants everything “just so”, and that will not earn you any points.