1.5.3 - CRITICAL bugfix for 1.5.2

In 1.5.2. "burn bootloader" was improperly configuring the pins on AVR DD-series parts that did not use optiboot in a maximally hostile and perverse manner, resulting in UPDI always being disabled, and hence, unless one has one of the small number of high voltage updi programmers that support the DD-series parts (programming tools treating them as if they were tinyAVRs would if one was lucky and/or careful, fail to work, and if one was careless and unlucky, instead cause hardware damage). Most of us do not have the appropriate HV programming tools, and hence would simply observe that "burn bootloader" would brick the chip.

It was a single letter typo, placing the pin configuration bitfields 1 position to the right of the correct one... and the higher bit which was thus always 0 which corresponds to disabling UPDI functionality. This error was only present on the non-optiboot definition, which is also the case in which the user is least likely to have any way to reprogram the device (the-less-flagrantly

Sorry about that...