Firmware update for G-Drive (firewire/e-SATA) 1 TB

Hi,

sorry for the newbie post, but i have an older G-Drive (on a Mac Pro 5,1) as a backup and the drive has failed.
I have now bought a 3TB to replace the 1TB that was in the drive and all the mac can see is 801MB, i believe it’s a firewire update thats needed, can anyone help as i don’t want to throw away a perfectly good drive, but i also need more storage to back up the 2 TB thats in the mac now (SSD main drive)

Thanks for any help

Mark