The uboot blob is combined with the rest of the firmware and flashed into the SPI. I did it over UART, using directions here: http://wiki.espressobin.net/tiki-index.php?page=Bootloader+recovery+via+UARTCan you please elaborate on the uboot steps?
What about the blob it produces? Do you simply flash it to the first sectors of the disk or do you place the file on the EFI fat partition?