If i unplug my iphone while its "updating software" will it restore the old software? or is this a bad idea?

Question

if i unplug my iphone while its "updating software" will it restore the old software? or is this a bad idea?

Answer 1

It's a bad idea. It *ought* to recover OK, but there are too many cases where it hasn't to be safe assuming that it will.
If, as Changren Yong says, you have a good backup, you always have the safety net of a restore, but it's a silly thing to do,
My advice when doing software updates is to download separately then update (you're always offered an option to download only). You can do what you like during the download, which is always the ling part of the process for me. The update usually (for me) only takes about 5 minutes.
One further point - in case you didn't know, you can initiate a backup by right-clicking the phone in iTunes and choosing Backup from the drop-down. That should always be part of your update process