USB PIC Bootloader

USB PIC Bootloader is a lightweight utility designed to help advanced computer users enhance their PIC18 Enhanced Flash USB Microcontroller devices by performing various operations.
By using this tool it is possible to program firmware application images directly into the devices chip by relying on its standard USB connectivity. Since it is fully compatible with USB specifications for HIDs (Human Interface Devices), all interface-related operations are performed by using standard Microsoft HID drivers.
Security-wise, this tool uses an XTEA encryption algorithm in order to protect the privacy of the firmware application image that was upgraded with USB PIC Bootloader. Since this applications code is write-protected, it is impossible for firmware to overwrite it.
USB PIC Bootloader comes with two separate modules that can be selected by software and hardware switching alike: a firmware and a user mode. This application uses the EEPROM mark in order to determine which module to use whenever it runs.
In the firmware update mode, this tool communicates with the PC by using the USB connection of the device, loads the corresponding code and switches to user mode afterwards. When the application is in user mode, it just remaps, interrupts and resets vectors back to user mode.