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Re: small custom bootloader to start an app stored in flash


Hi,

I agree!

Redboot is a great piece of software. It is just I found that when you enable some important features like FIS support, Redboot reserves extra space in RAM memory. The size of this reserved extra space in RAM equals to the size of the largest section size in Flash. In case of stm32f407 it is 128KB. Internal RAM is 128KB. As John Dallaway pointed out there is very little sense in using Redboot without enough of external RAM on stm32f4 devices. For example for Kinetis it is a different story, the flash sections are uniform and quite small.

For small systems external RAM chip significantly adds up to the cost of a device.

Best wishes,
Oleg
On Thu, 23 Oct 2014, Oleg Uzenkov wrote:

At last got some progress! :-)
Congrats!

[snip]

   HAL_PLF_ARCH_GETRESETVECTOR(exec, 0x08020000);
                                            ^^^^^
Oleg, you reserve 128K for "small custom bootloader", 128K is more than
enough to use RedBoot. If you can donate 128K for boot-loader then use
RedBoot.  I am sure that RedBoot can run and your "ROMROM" applications.
If standard RedBoot lacks some behaviors, just provide new functionality
with custom RedBoot command(s) FYI: this code can be part platform HAL.

Paraphrasing  Greenspun's Tenth Rule, Any custom boot-loader for eCos
will contain an ad hoc, informally-specified, bug-ridden, implementation
of half of RedBoot :-)

I assure you if you can donate 128K for your own bootstrap code then
using RedBoot will save your time and efforts.

Sergei



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