Content originally posted in LPCWare by Floyd42 on Mon Feb 03 04:44:37 MST 2014
Refering to that thread, this guy says: "The electronics connected to PIO0_1 did pull it down, I fixed this and now it working again.". So this is not a surprise then and basically a user's fault. And adding an external pull-up then may also not help much when the unspecified "electronics connected to PIO0_1 did pull it down".
Please note that my question is about proper documentation and clarification what the bootloader does. So far it seem the bootloader does not modify anything, so the defaults hold and the pull-ups for Reset and ISP are on. And thus levaing the pin floating should be safe actually. Adding some more details in the UM for clarification may also help the beginners. But if things are not really explained, people start believing in magic and words some some forum gurus (that may not even apply to the chip they are using). Forums are also full of such examples......