I'm running into one of the known netbooting bugs. I can't boot the rpi 3 unless I put the bootcode.bin on the SD card. Fetching over the network is not possible. The rpi is directly connected to a mainboard which hosts the tftp server but it seems the interface on the server does not come up fast e...

The boot through USB keyboard or serial sounds interesting. Any links for that? I would be ok with using the normal SD card pins for SPI booting. There are also SD card extender cables so maybe one would not need to solder something on the board. It may also be possible to boot via a SPI EEPROM atta...

Other boards can be booted from SPI through the GPIO pins : https://linux-sunxi.org/Bootable_SPI_flash
Is it possible to do the same for the rpi 3 and just connect a SPI flash chip to the right pins?