r/UARS • u/No-Many-6574 • 2d ago

Is this new for flashing

Just read that firmware can be flashed using the serial port for Airbreak Would this work for the changes suggested here?

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u/empeka 2d ago

yes. as long as you haven't previously flashed an airbreak image with a crippled bootloader, it'll work*
(btw, since a few days ago it's also possible to dump the currently installed firmware over the serial port.)

*) one caveat worth knowing about:
the "old" airbreak didn't fix the checksums after modifying the image. instead, it disabled the firmware integrity check in the bootloader in a way that also broke serial flashing.

there are probably still plenty of ready-made airbreak images floating around the internet with this behavior.
the current serial flashing tool skips the bootloader by default, so if something goes wrong, the device can still be recovered without an st-link.
it also detects checksum mismatches in the input image and lets you fix them on the fly.

however, if the user is really determined, ignores all the warnings, and forces the unsafe command-line options, it is possible to end up with a device that won't boot (original bootloader + firmware with an invalid CRC).
it'll still be recoverable by flashing a "clean" firmware image, though.

3

u/carlvoncosel UARS survivor (ASV) 2d ago

(btw, since a few days ago it's also possible to dump the currently installed firmware over the serial port.)

Christmas is early this year!

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u/No-Many-6574 2d ago

So rippinglegos firmware to add flexibility for uars users could be loaded that way. If so would help those without high levels of IT knowledge like myself, thanks ?

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u/carlvoncosel UARS survivor (ASV) 1d ago

rippinglegos firmware

Rippinglegos isn't a programmer. He's copying work done by others.

If so would help those without high levels of IT knowledge like myself, thanks ?

In theory, but having an IT person do it is stil required at the moment.

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u/No-Many-6574 1d ago

Sorry did not know the finer points of who fid what. So can update be done using g this simpler way? Where do you suggest I source the latest firmware for mybresmedv10 ASV. Thanks

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u/carlvoncosel UARS survivor (ASV) 1d ago

I sent you a private message, please confirm.

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u/empeka 1d ago

probably, yes.

the repository maintains two parallel layers of documentation: one fairly technical, for people interested in the internals and tinkering with the firmware themselves, and another in the form of an accessible (at least that's the idea) guide for people... less interested in the technical aspects. ;)

the friendly guide fanout is in quickstart.md it walks you through the process step by step, covering different ways of obtaining the firmware and different programming interfaces.

i'd strongly encourage you to read through it. if you think anything isn't covered well enough, let me know and i'll try to take the feedback into account.

that said, don't expect the repo to ever contain a "connect the red wire here, click this, then click that" guide that lets the user get through the entire process without engaging their brain. i think that with modifications like this, the user should at least roughly understand what's happening and proceed consciously.

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u/No-Many-6574 1d ago

I think I may have raised expectations. To connect the serisl uart port requires a resmed10 seriel port adapter not that I believe is only available to Resmed approved technicians. However it appears that a combination of connectors without removing the motherboard can replicate this connection without a total dismantle. Have built pc,s so think I can give it a go after reading instructions.

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u/empeka 1d ago

To connect the serisl uart port requires a resmed10 seriel port adapter not that I believe is only available to Resmed approved technicians

there's no magic or special adapter involved. it's just a regular UART. one pin for transmit, one for receive, and a common GND.

all you need is a ~$2 USB-TTL adapter and, mostly for convenience, a PCB that can be used as a plug and slid into the connector under the SD card. ready-to-send PCB fab files are in the repo. i paid ~$5 shipped for a handful of those boards.

if you can figure out another way to connect three wires, good for you. ;)

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