Looking for TINI SDK
I just found a mirror of the old SDKs on ...

Grab it while it's still there!  (I can confirm the download, just pulled it down myself)

Kind regards,
Andi

PS: I forgot how to do the firmware uploads, it was a normal RS232 but needed DTR/DSR (I think) as well to put the device in flash mode.  Ah, coming back to me now, just check the docs/ directory.  Only problem you (and I) may face is that the upgrade needs a minimum prior version on the device, meaning you may have to download another earlier version to bridge a very old firmware to the latest 17