Is it possible upgrade firmware online to STM32F4xx by Tinygo?

[hgmmym]

WOW, I don't even know Github has discussion function......

Well, I'm using STM32F407, and I can connect to network through this development board.
Assuming I can download the bin file to the board, how can I upgrade the firmware?
Like a Boot-Loader or something?

I'm sure it's able by C, I can write the bin data into ROM. But I'm not sure if this feature can be implemented by Tinygo.

[sago35]

Currently that feature is not implemented in TinyGo.
However, if it is possible in C, it can be ported. Alternatively, CGo may be able to solve this problem.

A link to the C language implementation would be nice.

[aykevl]

There are various ways to implement this sort of thing, and all of them rely on a bootloader of some sort. Basically, a separate stripped down firmware that handles some part of the upgrade that cannot be done on-the-fly (you can't rewrite the firmware that's currently running).

Some common designs are:

• Application firmware downloads new firmware, stores it somewhere (for example, on external flash), and reboots to a small bootloader that then copies the new firmware over the old firmware.
• The application reboots to the bootloader for upgrades, and this bootloader downloads the new firmware. Once done, it reboots into the new firmware.
• There are two firmware areas (A and B) that are full application firmware areas, and a very small bootloader selects which one to boot on startup. Android phones typically use this, called "seamless updates". This is difficult to implement on a microcontroller, though.

I recommend looking into existing bootloaders instead of trying to reinvent the wheel. It's very easy to screw up, and you don't want to have bugs in the OTA mechanism especially when it's somewhere in a hard to reach place.

One popular bootloader seems to be mcuboot, you could take a look at it. I haven't used it personally.

Oh and to be clear, this usually requires little cooperation from TinyGo, apart from some linker script tinkering (to avoid overwriting the bootloader). We already have some boards that use a bootloader.

[hgmmym]

@sago35 That's what I thought. Let me have a try. Start with a C bootloader, then jump to the address where the tinygo firmware started.

@aykevl I'm wondering, is there a way to allow tinygo to directly write data to the specified ROM address? I mean, I can download the tinygo bin file, but how can I write it into ROM if I don't have external flash? I can write the new bin into the blank spaces where tinygo didn't use.

STM32F407vgt6 has 1MB ROM storage. If my bin file is less than 400KB, it could be something that can be done... OK, just do it, now.