dual bank boot STM32F437 vs STM32F439

[graffiti]

Posted on October 24, 2014 at 16:14

Hi,

I am using a STM32F437 and need to use the dual bank boot feature to perform live firmware updates. I have the boot0 pin tied to ground.According to the Reference Manual:In STM32F42xxx and STM32F43xxx devices, when booting from the main Flash memory, the application software can either boot from bank 1 or from bank 2. By default, boot from bank 1 is selected.To select boot from Flash memory bank 2, set the BFB2 bit in the user option bytes. When this bit is set and the boot pins are in the boot from main Flash memory configuration, the device boots from system memory, and the boot loader jumps to execute the user application programmed in Flash memory bank 2. For further details, please refer to AN2606.However, checking AN2606 it appears that the dual bank boot feature is only available in bootloader V7 or V9, and the STM32F437 is only available with bootloader V3??!Checking the bootloader version at address 0x1FFF76DE confirms that I only have V3.So my questions:- are there any plans to update the bootloader in future revisions of STM32F4x7, or am I required to use a STM32F439 if I need the dual bank boot feature?- is there another way to boot from flash bank 2 on a F4x7 device? (without having to partition up the flash and have a first stage boot loader)Thanks,Kieran. #dual-boot

[Tesla DeLorean]

Posted on October 24, 2014 at 17:33

- is there another way to boot from flash bank 2 on a F4x7 device? (without having to partition up the flash and have a first stage boot loader)

If you want to retain ownership of the behaviour you might need to be more flexible. The BFB2 thing is an awful hack anyway, just  code something trivial in the first 16KB of each bank, doing the remapping, and providing better protection against totally bricking the chip. The System area is OTP/FLASH, as far as I'm aware, so ST might well have newer versions. Check with your FAE

[graffiti]

Posted on October 25, 2014 at 18:34

Thanks Clive,

I'll look in to writing a small remapper/loader.Cheers, Kieran.