Red flag. Never work on company stuff on personal machine. They need to get their act together and provide equipment. You show up; you get paid--even if they are still provisioning your equipment.

In the meantime, shadow folks, attend standups, get to know your colleagues, the products, etc.

That's my plan, or they can buy my existing laptop at market rate on the spot and I will happily flash it. But in all reality they can walk down to Union Square Apple store across the street and pick up a MacBook.