Thanks guys!
I won't try it then!
I was asking because on the board I'm prototyping, I wanted to program ATMega chip via ISP header before I added voltage regulator. My ISP programmer supplies 5V... No biggie, I'll just need to supply voltage separate (make and adapter cable)....
BTW speaking of frying things, voltage reversal is of course something else that very bad for ICs, however I keep doing it over and over again (accidentally) and I learned few things on the way. AVRs seem to handle voltage reversals without any ill effects (for a short time) in my experience. So do some other ICs, like TH02 sensor for example. On the other hand, never do this to OLED display
Mine started to smoke like crazy, and I only connected it for a second or two. Same goes for DS1308 RTC chip..