Basic question: Unresponsive sketch bricks Leonardo or Micro?

Despite my experience with UNO and MEGA, I am only starting to develop projects with these 32U4 based arduinos. one thing I found out was that they brick a lot. Say I do a real time clock project code and the wire.begin() is stuck, maybe bad backup battery, then I couldnt use the board until I reflashed bootloader. Is this normal?

More serious question: if sketch is stuck, will arduino ide be able to reset the mcu at all? After all, there is just one chip. If it is stuck, its usb serial is stuck, too, right?

Hung code can prevent the automatic reset from working, but a manual reset should get you back to them bootloader without actually having to re-burn anything.

Thanks. I counted about 7 seconds between bootloader starting and exiting. During this time its serial port is visible. Should i use this serial port to quickly upload a blink? My sketch will hang if it runs again.

Yep. As mentioned recently in other threads, each Leonardo sketch has its own serial USB code. If your sketch malfunctions sufficiently, this will fail to detect the 1200bps auto-reset sequence, but a manual reset should still run the bootloader from flash, and it has it's own USB code.

Thanks. I will try later day. I didn't know the bootloader port also accepts the 1200 baud for reset. It seeme a lot more difficult than an Uno. The end user of my design might appreciate an Uno like experience.