Creating a firmware file

Hello, I've been learning the device firmware upgrade using the u-boot bootloader. In order for me to make my upgrading convenient, a firmware file could be of great help. My problem is I am not familiar of the format of a firmware file. How do I create this file? Been googling around for some answers but haven't found a satisfying one. Resources could be of great help. Thanks a lot.

It is probably the configuration of the FPGA chip(s) on the board. These are created by a kind of compiler, usually part of a development system provided (sold, usually expensive) by the FPGA chip manufacturer. To modify it, you will need the original source code or detailed knowledge of the hardware as well as an understanding of the original purpose of the FPGA. You will also need a method to install the firmware onto the FPGA. Often, this is performed with a JTAG interface. There are commercial JTAG dongles available, but they are often part of the FPGA development toolkit as well. The FPGA code is probably considered proprietary property of the board OEM.

--- rod.

I'm sorry for the confusion (wasn't supposed to use the word "format") but I was refering to the uImage of the kernel and the rootfs contained in one file. Could it possibly be done by concatenating them and creating a .bin file with initial header and a checksum sector?

I was actually the one who is confused, lol. I'm sorry, it should've been "firmware file" or "firmware image".

There should be rules in the kernel Makefile(s) to re-create the kernel image with an init ramdisk.
--- rod.

I used buildroot to build my uImage file and my rootfs. I will try to look it up in my kernel makefile.