I decided I should try to replicate what happened to you. I set my iPhone auto-lock to 2 minutes and ran the update from the iOS client. I watched it as it went along. Turns out, it didn't break the STM32 firmware or the bootloader (which is what you've been reflashing - successfully actually). It instead auto-locked and disconnected at about 50% of the way through the nRF51 MCU firmware update.
You can reflash the nRF51 MCU pretty easily doing the exact same thing you did in the first place, use the iOS client update feature!
Try this:
1) Just like you did for DFU, unplug the battery, hold the power button and plug the CF2 into USB. Hold power until the first blue light flashing speed starts (a little less than three seconds). When you let go of the power button, both blue lights (M2 and M3) should flash - you're in the bootloader now.
2) Set your iPhone auto-lock to Never (Settings->General->Auto Lock). Plug your iPhone into a power source (just in case
).3) Launch the Crazyflie client app on iPhone, go to Settings screen and hit the "Update" button.
4) Wait about 10 minutes and you should see the "Success" alert telling you to restart your Crazyflie.
5) Disconnect the USB and reconnect the battery - CF should restart and you should be good now.
6) Change your iPhone auto-lock setting back to 2 minutes (or whatever you prefer).
So, I hope that gets you back flying and I apologize for leading you astray for a few posts there! Happy Holidays!!
BTW, I did learn a lot from this venture (like dfu-util 0.8.0 seems to have an issue with the STM32, and nRF51 doesn't necessarily need a Crazyradio and cfloader to reflash) and I've also logged a bug against the iOS client to prevent auto-lock when updating FW.
