Update boot-improvements.md

[cryptonome]

Choose one of the templates below:

Fingerprint

This pull requests adds a fingerprint for <Make - Model - Year - Trim>.

This is an explorer link to a drive with the stock system enabled: ...

Car support

This pull requests adds support for <Make - Model - Year - Trim>.

This is an explorer link to a drive with the stock system enabled: ... This is an explorer link to a drive with openpilot system enabled: ...

Feature

This pull requests adds feature X

Description

Explain what the feature does

Testing

Explain how the feature was tested. Either by the added unit tests, or what tests were performed while driving.

[Gernby]

This looks really promising! I'm curios how the dtoverlay works though. If you have multiple lines assigning a value to dtoverlay, won't it just take the last one? Here is the existing usercfg.txt that gets copied into the firmware folder during install.

https://github.com/Gernby/raspberry-pilot/blob/resonant-rails/phonelibs/usercfg.txt#L4

[Gernby]

I'm planning to test these on my SD card, since I think they could be very beneficial for the new multi-model approach.

We may want to turn bluetooth back on at some point, if we want to send audio messages to the head-unit, but I like the idea of disabling it until then, if it offers benefit.

[Gernby]

I haven't checked Google yet, but do you have any links to some good testing results about the SD card clock rate?