2 second (slow) boot time / custom boot loader?


I noticed that it takes about 2 seconds after power on that the code in setup() gets executed. Why is this? I see the same thing whether I power the device from USB directly of Vin.

I also wonder if the bootloader is open source? Does anyone have a link to the source code?


Hi Sebastian,
unfortunately I have the same topic to be solved.
Has anybody a hint to solve this problem?


Hi guys, I guess this is a pretty old post now but I’m having the same issue with my Xiao’s and was hoping to find another bootloader or something to address the slow startup time. I’ve worked with other boards recall them having a setting for it in the bootloader but I have no idea if that’s the case here. Has anyone else made any progress on this?

All machines need a certain start-up recovery time. A start-up time of two seconds may be a relatively acceptable range. Perhaps we can be patient.

That doesn’t really work for portable (battery-powered) electronics where the user expects the device to power up relatively quickly and they generally get the impression its malfunctioning if it doesn’t. That’s not a very good look.

On top of that, the very same microcontroller used in this product can and DOES boot up near-instantly in other almost-identical products such as a trinket m0 or gemma m0 to name a couple, so it’s very likely within the capability of the product with the appropriate software/firmware.

Perhaps we can refrain from commenting if we don’t have anything helpful to offer the conversation? But seriously, thanks for calling us impatient when we asked for help, you’re so awesome!

I think you may have misunderstood what I mean. Most of our products need a waiting time when they are up and running. During this time we think it is normal, so we are very sorry for this problem and did not help you, but it is related I also gave feedback to the product designers based on your suggestions. They also said that they will pay attention to this issue in future product development, but for customers who have already purchased, we can only hope that you can wait for it to run for a while, thank you.
If some expressions made you feel disrespectful before, I am very sorry here.

1 Like

Pot, meet kettle …

1 Like

Understood, thank you for clarifying

thank you for understanding.

1 Like