How I made a new T-mobile SIM card work on iPhone 4S with my "New GPP" unlocker card

My situation. I have an iPhone 4S from Mexico. It's carrier locked to Iusacell.

My previous setup was that I got one of the newer gpp chips (idk if its pro, turbo, or what, it only says "new") and put it in with an AT&T prepaid originally. The gpp menu came up and I entered the locked carrier's IMSI, which worked. But my AT&T plan didn't offer cellular data so I wanted to switch to the $30 unlimited text & data plan from T-Mobile USA.

Long story

I ordered T-Mobile's SIM card activation kit online (it's twice as expensive in stores) and when I finally got it my plan was to simply change the old SIM card for the new one. When I did, the iPhone simply registered "No SIM". Upon restarting, it showed "Searching..." for a bit and then back no No SIM (with a "No SIM card installed" alert). I tried not to panic and thought I needed to activate the SIM card first, so I tried to do so online but it seemed to take too long so I ended up calling T-Mobile instead and they activated the card and the desired plan for me. They said it would take a few hours for it to start working.

The next day I was still reading "No SIM". I tried this desperate method (switching airplane mode on and off repeatedly, which sounds silly) to no avail. I tried using the GPP config SIM but could never get back to the IMSI input menu of GPP... But the old SIM still worked with the GPP, so nothing seemed to be damaged!

Finally

After work, to check whether GPP would work with other companies, I asked someone to let me try their SIM card. It was Sprint. "No SIM". This time however, I did the airplane switch method and something happened, the Carrier section in Settings appeared! I quickly entered it and selected T-Mobile (Sprint didn't even come up, funny) but still I never read Sprint as the carrier, so I thought that was of no consequence and that the GPP would not work with T-Mobile or Sprint for some reason, or maybe my SIM card was bad? Who knew... HAPPILY, When I re-insterted my T-Mobile SIM card (with the GPP), it magically worked!

So it seems having selected the carrier manually may have done the trick, however this was impossible while I didn't have the option to do so while "No SIM" was indicated (and no Carrier section was displayed in Settings). Also, the carrier settings with the previous SIM card didn't include T-Mobile (I think).

Anyway, it works now. Yay


p.s. Make sure Data Roaming is enabled to get 3G (as indicated here).

Transfering among MTA buses (NYC transit)

There's one big limitation not described in the MTA's website about bus-to-bus transfers: you can't transfer into the same bus line. Why would someone want to? How about a quick stop in the store that's on the way home? (e.g. Whole Foods - Houston Street for the M21 bus.)

This is not indicated in the paragraph about "making connections" of the bus riding webpage:
"If you pay your fare with MetroCard, you may transfer free from local bus-to-subway, subway-to-local bus or local bus-to-local bus within two hours of the time you paid your fare. Unlimited Ride MetroCard includes all transfers free of charge..."

Clearly, using the same local bus line twice falls in the bold-ed scenario, but of course, they don't allow it. I find this annoying, why so freaking strict? I really dislike the MTA (too bad shitibike sucks almost as bad).