Just to add to Martin's note...
If that 0x8001 restart doesn't work on this device,
I2C restart is the same as stop/start in functionality, just a bit quicker.
So a write transaction of 1 byte with the register address, followed by a read one byte transaction should work equally well.

Another possibility is using crontab @reboot (with a sleep)

Hi, If you use the RX interrupt, then you should only process one received character within the called macro, putting it into a circular buffer is the best approach. Then in your main macro use the circular buffer commands to determine when you have received a string and process it. (You can't mix i...

These changes relate to the recent adoption of systemd. As a user of Unix/Linux for several decades it's all unwelcome changes for me

Thanks for the heads up on that, just to add a bit of caution... /home/pi/.bashrc will only run when you log in, which happens automatically when you boot up and go directly to the desktop and also every time when a new terminal is opened, or when a new SSH connection is made. A search found this, b...

"!1" ?
That won't toggle.
As usual, it's best if you can attach your program file, then we can see what exactly you are doing.

How are you measuring it?
If you are toggling an output pin then you need to factor in those instruction times, and any loop/jump, as well.

Yep, AI is wrong, as usual
Depends what you asked though.
Your screen shot method is correct for UART baud.

C13 is user LED (active low)
C14 and C15 are RTC crystal

Ah right. I guess we need to look at the Blackpill circuit diagram and 411 datasheet to answer that one