The incomparable ladyada tells us:
The next version of the Mintyboost is done and documented. This time it’s based on the LT1302 chip instead of the MAX756, which can provide up to 600mA (although I’ve found that with 2xAA’s it doesn’t really go past 450mA). The layout was also improved for better efficiency. The upgrade was necessary as the latest Apple products really need a lot of current to charge and hopefully they will work better now!