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K22 MCUBoot Drag and Drop *.sb file to SPI Flash

Question asked by Gary Sinde on Feb 16, 2019
Latest reply on Feb 27, 2019 by Gary Sinde

I would like to be able to drag and drop multiple *.sb files on to the USB Mass Storage Device. Currently, I can drop files (linked to address 0xA000) as much as I want but I also need to pre-configure my SPI Flash with LCD Splash Screen (75 Kbytes each), other binary files (40 KBytes each), etc. and these may need to update in the field. Sure, I can link them directly in my code but eat up valuable main flash space.


So, In production, I would like to install MCU Boot (my modified one of course) with Kinetis Flash tool or whatever.

Then, drag and drop SPI Flash *.sb files and load up my SPI flash. Then lastly, drag and drop the file and reset the device and DONE. 


In the field, a customer can hold down the power button (only button I have) for two seconds and the devices will stay in bootloader and mount the USB mass storage (FSL Loader). (This has been modified and works). Then drag and drop update files supplied.


I only have USB exposed in the bootloader (HID and MSC) because all other pins are busy running peripherals in my application. The LCD on the Flex Bus consumed a lot of pins and I am using LPUART.


Anyone try this or have a gut feeling whether it will work? The trick is understanding how the bootloader parses the SB files in real time and redirect the writes from main flash to SPI flash. (I am using MK22FN512 CPU with 16M SPI Flash.