Where is the super simple boot loader and file up loader?

[AMarch]

I know I am going to regret posting this question, but I need to ask it.

I have an application that will be put into the nrf52840 chip. It will not be upgraded over the air. It will be upgraded through spi. It does not have a soft device and probably won't have one. It is behind another processor so it will not need any security to speak of, if someone has compromised this part of the system  there is little chance that protecting this piece will matter.

What i need is simply a boot loader that detects when NRF_POWER->GPREGRET equals a flag, which means the main application has set the flag and initiated a soft reset.

I need to check if the hosting processor really wants to talk .

Copy in a compressed .hex file with the new application , a binary version of the .hex file for the new target.

Validate that binary. (something a better then CRC16,)

Move that application to the target area , using the decoding of the addresses from the .hex file

Set a flag saying we are good, reset and jump to the new program.

Thats all I need. I don't need to sign the code or anything that excessive.

Where are the switches in all these libraries to just take in the code and move it into place...reboot

Tony

[Nguyen Hoan Hoang]

There is a version of the Nordic bootloader that does not require encryption.  It's in the SDK. You can use either USB or UART version and replace it with your SPI backend.  Look in the SDK examples/dfu/open_bootloader folder. 

[AMarch]

Yeah i knew i was going to regret posting this.

I looked at this project already, but dismissed it because the project was laden with all the nrf_Crypto folders. I built it and it showed 942KB of (91%) flash usage, which confused me.

Why does this project need any crypto libraries at all? Tracing through the build i see that it is still using crypto init. Seems to be using it for the hash function, is that all it is doing?

I'll take another look. I need to put this stuff on here to calm down or something.

Thanks for the re-direct.

Now I need to sift through this site and see if I can find where the host code to go along with this , might be.

Was that a blog post?

[Nguyen Hoan Hoang]

I compiled the USB version and it's about 32KB.  There must be something wrong in your compiler settings may be.  The host code can be found on Nordic Github in nRFConnect projects or nrfjprog project. I never looked inside those projects so don't know what's in there.

[AMarch]

Ok I am looking at the project and documentation , Kind of be nice if there was a README associated with it that explains the proper way to locate the target file to load into the firmware, but that is another issue.

This project (as stated in the documents) uses USB. So I assume to make it work totally serial, i need to

• rip out the USB device drivers.
• remove nrf_dfu_serial_usb.c from the project
• add nrf_dfu_serial_uart.c to the project
• probably some uart configuration in there

Assuming you or anyone has done this, does this seem reasonable?

[AMarch]

Also notable in this project, the baud rate of the USB device doesn't appear to be clearly specified, unless it doesn't matter.

I was going to test some back and forth over the USB UART port , and generally you specify a baud rate, one isn't listed, ill just have to try whatever.