Q: using a thunderbolt to firewire, then a firewire to usb

There may be a way to at least try a few adapters and appropriate cables to see

if there may be a connection from Thunderbolt in the newer Mac to USB in older.

A Sonnettech or Kanex 'thunderbolt to eSata + USB3.0' adapter may be attempted

to see if that, plus a USB cable the the same ends on it (or reverse adapter) could

go from the USB3.0+eSATA to Thunderbolt, and connect to the internal USB port.

Most cables needed for the final leg of this are harder to find, looking at images.

Both more common of available adapters are on this page; still lacking is a cable:

http://www.bhphotovideo.com/c/buy/Thunderbolt-Cables-Adapters/ci/17952/N/4042754 092

Kanex Thunderbolt to eSATA and USB 3.0 Adapter

Sonnet USB 3.0 + eSATA Thunderbolt Adapter

Some adapters do not have an ability to convert one native signal to another, so if a

situation exists where some aspect of signal cannot or isn't able to pass, its a no go.

See in image detail where the adapter box provides a port for cable plug, so the cable

would need to have another similar plug to input to the port in the computer, to connect.

And I don't yet see such a cable; I used to have an adapter for the end of a printer cable

to change the end to a regular cable but haven't seen or used one that two same ends.

Anyway, the time here is near 2AM and I thought to look into a few sites and search for

some ideas; for a few years now these main adapters have been available. The last item

is a cable plus reverse end so both similar ports can be connected. The adapter and the

older Macbook with USB. There may be an easier way to use the old MacBook in Target

Disk Mode, with a newer Mac that has no FireWire and no Thunderbolt ports.

Short of acquiring a universal drive adapter kit & remove drive from old MacBook, to access

just the bare drive by the kit (it has power adapter and cables to attach HDD by USB) as:

http://eshop.macsales.com/item/NewerTech/U3NVSPATA/  - universal drive adapter USB

So I'm going offline and hope you can make a patchwork connection or an alternative route

to connect those products and resolve the mechanics of this issue.

Good luck & happy computing!

Firewire Target Disk Mode doesn't work over USB. How to use and troubleshoot FireWire target disk mode - Apple Support

Other than connect the two computers what are you trying to accomplish? Maybe if we knew that we could offer another suggestion.

OK, I was a bit confused in my late hour auto-pilot missive above since my Macs

all (seem to have) USB, and FireWire, and one has Thunderbolt too. Those certain

models that have no FireWire ports I tend to avoid; & yet had read about this once.

The new (2015) 12-inch MacBook Retina with USB-C can boot Target Disk Mode via USB.

http://www.macworld.com/article/2911813/got-a-new-macbook-usb-target-disk-mode-

works-with-the-right-cable-which-apple-do…

Via: • Using the USB-C port and adapters on your MacBook (Retina, 12-inch, Early 2015) - Apple Support

But that doesn't have an equal since FW doesn't necessarily carry the same signals via adapter

and/or the computer doesn't recognize them at various starting points as available, & so on.

To remove the hard drive and use the USB adapter kit such as one from OWC macsales mentioned

could be one of a few ways to access the computer drive in question, lacking other connections... re:

http://eshop.macsales.com/item/NewerTech/U3NVSPATA/  - universal drive adapter USB

Thanks for reminding me...