The i.MX RT Series is industry’s first crossover processor provided by NXP. This document desribes how to program a bootable image into the external storage device. The i.MX RT1050 Flashloader is an application that you load into the internal RAM of a i.MX RT1050 device. The Flashloader is designed to work as a second stage of Bootloader for i.MX RT1050 device, it detects communication traffic on one of the the supported peripherals (USB-HID and UART), download a user application, and write the application to external Serial NOR or Serial NAND Flash device. The Flashloader is loaded by MfgTool at first stage and work with MfgTool to do Flash programming at second stage. The release includes the PC-hosted MfgTool application, this application is used for downloading application to Flash device in both development phase and production phase. This release also includes elftosb command-line application, it is used to generate bootable image for i.MX RT1050 ROM and generate programable image supported by Flashloader. or Serial NAND Flash device. The Flashloader is loaded by MfgTool at first stage and work with MfgTool to do Flash programming at second stage. The release includes the PC-hosted MfgTool application, this application is used for downloading application to Flash device in both development phase and production phase. This release also includes elftosb command-line application, it is used to generate bootable image for i.MX RT1050 ROM and generate programable image supported by Flashloader.