pull down to refresh

but it's not limited to raspberry pi, any hardware can have that. But the raspberry pi by default uses uboot as "bios" which is opensource, so maybe it's more secure than x86 with IME if you're not using coreboot/libreboot. Do I get it wrong? On the raspberry pi one can also use tow-boot: https://github.com/Tow-Boot/Tow-Boot