June 16 (Reuters) - Micron Technology (MU.O) on Friday warned of a bigger hit to revenue from a Chinese ban on sale of its chips to key domestic industries, sending the memory chipmaker's shares down about 2%. The company said it now expects an impact on about half of its revenue from China-headquartered firms, which equates to a low-double-digit percentage of its total revenue. It had earlier flagged a hit in the low-single to high-single digit percentage. Micron was the first U.S. chipmaker to be targeted by Beijing after Washington imposed a series of export controls on certain American components...