Feature Request: I²C Bootloader to ATtiny1626 (modern AVR 0/1-series support)

[Qualoquash]

Hi there,

I’m working on a school project where I’m building a modular Battery Management System . Each cell in the battery pack has its own microcontroller (20 in total), and they all communicate via I²C.
To keep things clean and minimize wiring, I’m flashing the same firmware to all devices and would love to be able to program them over I²C instead of using UPDI individually.

I came across the Keyboardio I²C bootloader, which looks like an ideal solution—except it currently supports older AVR chips (like the ATtiny88), and not the newer AVR 0/1-series chips like the ATtiny1626. I chose the ATtiny1626 for its features, especially the 12-bit ADC.

Would it be possible to adapt the I²C bootloader to support the ATtiny1626? Or is anyone already working on something similar?

I’m relatively new to bootloader development (mostly familiar with Arduino-level programming), but I’d be happy to test and help however I can.

Thanks in advance!
David

[obra]

Hi David, It's certainly plausible to implement and I'd be very happy to review a pull request if it's something you want to work on. Best, jesse

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On Mon, Jul 28, 2025 at 4:10 PM Qualoquash ***@***.***> wrote: *Qualoquash* created an issue (keyboardio/attiny_i2c_bootloader#12) <#12> Hi there, I’m working on a school project where I’m building a modular Battery Management System . Each cell in the battery pack has its own microcontroller (20 in total), and they all communicate via I²C. To keep things clean and minimize wiring, I’m flashing the same firmware to all devices and would love to be able to program them over I²C instead of using UPDI individually. I came across the Keyboardio I²C bootloader, which looks like an ideal solution—except it currently supports older AVR chips (like the ATtiny88), and not the newer AVR 0/1-series chips like the ATtiny1626. I chose the ATtiny1626 for its features, especially the 12-bit ADC. Would it be possible to adapt the I²C bootloader to support the ATtiny1626? Or is anyone already working on something similar? I’m relatively new to bootloader development (mostly familiar with Arduino-level programming), but I’d be happy to test and help however I can. Thanks in advance! David — Reply to this email directly, view it on GitHub <#12>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAALC2HARJBBRQAGUL4KR3L3KZ7TFAVCNFSM6AAAAACCR5XNUKVHI2DSMVQWIX3LMV43ASLTON2WKOZTGI3TCMRQGQYTSNI> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[Qualoquash]

Thanks a lot for the quick reply!

As I mentioned, I’m still very new to GitHub and programming—especially when it comes to bootloaders—so I’d probably need quite a bit of guidance, if that’s okay with you.