We have user-installable upgrade boards for Tensors with serial number 108-066999 and below. After the upgrade, your Tensor will have the same specs as later Tensors: 9.4 second mono / 4.7 second stereo maximum loop time, stereo input/output.
See the product page for information and a video showing the installation procedure.
We don't make money on these boards; they are assembled in lower quantities at a different factory than our normal production, so parts and assembly cost are both higher.