beaglebone serials (eeprom vs label)

perl -Mautodie -E 'my $path = "/sys/bus/i2c/devices/0-0050/0-00500/nvmem"; $path = "/sys/bus/i2c/devices/0-0050/eeprom" if -w "/sys/bus/i2c/devices/0-0050/eeprom" || ! -f $path; open my $fh, "<:raw", $path; sysread $fh, $_, 0x70, 0; s/[^ -~]{1,32}\z|X{9}\z//; say for grep $_, unpack "x4a12a12x52a32", $_'


----- older beaglebone ---------------------------------------

script output:
        A335BNLT00C0
        4215BBBK0789
        400524+1301+001929+1542

breakdown of second line:
        42              week number
          15            year without century
            BBBK        (fixed string)
                0789    serial number in hexadecimal

printed on label:
        400524          (fixed string)
        1301            (fixed string)
        001929          serial number in decimal
        1542            year and week number


----- recent beaglebone ---------------------------------------

script output:
        A335BNLT00C0
        2251SBB10986

breakdown of second line:
        22              year without century
          51            week number
            SBB         (fixed string)
               10986    serial number in decimal

printed on label:
        BBBVC           (fixed string)
        202212          year and month
        010986          serial number in decimal