Because the last few days to give the factory app and bootloader hex file, many online are bin merge method, bin method no longer repeat, I believe we can find, now will hex merge method write down:
First step: First hex file is opened,
Step two: Select "merge data file" to merge files
Step three: Two projects may have the same address, there will be the following tips:
At this point, click "No", then turn off the bootloader hex, open the app's hex, change the address.
Select Edit->relocate, at which point the offset of the write address is required, and you need to see where the address of the interrupt vector table of your app is written, write the address, and click Save.
Then repeat the above steps and then click File->save Data File as ... Save it as a hex file, and the hex file will be merged.
Using the Jink driver software j-flash Merge two hex methods, Bootloader+app