I'm working in a Scrum project writing firmware code in C for an ASIC.
Every so often we have really hard to find bugs. But how do I time estimate these bugs?
I always tell the Scrum master I do not have the competence to estimate them because I really hate time-estimation of bugs.
How do you guys handle this in your Scrum projects?
Estimating bugs is a really hard thing. If you can do it, then you likely already have the solution and it's not really a bug anymore :) So, instead of trying to estimate them one by one, my preferred option is to allocate some "bug fixing time" during the Sprint and to fix most important bugs during that time. This is a best effort strategy, you just fix as much of them as possible during the allocated time.
We can classify bug in "I know where it is going wrong I need to update it", "I know this bug is related to this module and any debugging some of these files I can resolve it", "I am not sure why this bug has come up". We can estimate in first 2 cases based on our experience on that project. But estimating for last case is real tough.