We are using LPC54628J512ET180 in some of our product. We are recently facing an issue about boot loading. We are keeping ISP0, ISP1 and ISP2 pins floating in our design , similar to the reference design of your SDK board. We have provided just push button switches tied to ground, to select boot modes, hence there is no provision to pull up them (this provision is also not found in your reference designs). We are facing the issue in boot loading the internal Flash of MCU. In some hardware the boot loader is unable to boot up the MCU from Internal Flash. We need to provide external pull up on hardware to get it booted up from internal flash. But this is not mentioned in your reference designs. So we would like to know, if the external pull up are really required or not ? or these pins are internally pooled up by default ?