Re: Raspberry PI and OE
- Posted by ghaberek (admin) Feb 15, 2021
- 964 views
You are certainly correct about the heat. I added a finned heat sink to the microSD socket, since it got extremely warm after a while. Later, I found out that it is easy to boot from an external SSD, so the card isn't needed anymore.
For anyone reading along, all Raspberry Pi devices since 2B+ can be set to boot from a USB mass storage device (thumb drive, HDD, SSD, etc.)
https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/msd.md
What's interesting is that the change to the firmware is permanent:
To enable USB host boot mode, the Raspberry Pi needs to be booted from an SD card with a special option to set the USB host boot mode bit in the one-time programmable (OTP) memory. Once this bit has been set, the SD card is no longer required. Note that any change you make to the OTP is permanent and cannot be undone.
And that also prevents some devices from ever being able to boot as a USB device itself (like, pretending to be a USB keyboard):
On the Raspberry Pi 3A+, setting the OTP bit to enable USB host boot mode will permanently prevent that Pi from booting in USB device mode.
-Greg
