Some boards manufactured in the most recent batch do not have MAC-IDs programmed in their EEPROM due to a manufacturing issue even though the correct MAC-IDs allocated to the board are shown on the three stickers close to the two Ethernet connectors. Please refer to the Premier P550 FAQ page https://www.sifive.com/boards/hifive-premier-p550/faq for instructions on updating the MAC-ID of your board.
Serial numbers of impacted carrier boards:
32GB: SF106CKB2450000001 to SF106CKB2450000090 and SF106CKB2451000013 to SF106CKB2451000300
16GB: SF106CKB2451000301 to SF106CKB2451000908