If your GoGear still detects but won’t hold charge, the battery is likely a standard 3.7V Li-Po (model number usually starts with “503040”). iFixit has teardowns.
The v3 ZIP file also includes a script (linux_mtp_detect.sh) that uses jmtpfs to mount GoGear on Linux. For macOS users, the ZIP contains a prebuilt QEMU script that launches a lightweight Windows XP virtual machine solely to transfer files to the device.