As you are running "Boot/Post 82000685 release_82000685_E", use the "Portserver TS8/16 Rev. G POST firmware". The file name gives it away as Digi does not change the internal numbers for firmware, only the letter. It is: "http://ftp1.digi.com/support/firmware/82000685_G.bin".
As you are running "Running EOS 82000684 release_82000684_K1" use the "Portserver TS8/16 Firmware Image". The file for this is "http://ftp1.digi.com/support/firmware/82000684_W1.bin"
Make sure you read the release notes and follow it EXACTLY. You can find the release notes for the W1 firmware here: http://ftp1.digi.com/support/firmware/93000408_W1.txt