I have been searching on Amazon and most of the USB dongle type Bluetooth 4.0 adapters specifically say not compatible with OSX. My question is; has anyone seen a Bluetooth 4.0 option to upgrade my early 2009 iMac without actually upgrading to the newest iMac?


3 Answers 3


Register as an Apple Developer for free with your Apple ID, search for Bluetooth Explorer on this page. After you installed the app you can plug in your Bluetooth dongle and open the app. Press CMD + L and pick your Bluetooth dongle from the list. Reboot your Mac and you're good to go..

This worked for me, I'm using a 2010 iMac with a Trust Bluetooth 4.0 dongle (both Mavericks and Yosemite).

  • @Cesar asked this question in a separate thread: "Does your solution provide Continuity feature to an old iMac (say 2009) or simply add BT LE functionality for other tasks?" I am reposting it here and recommending the other thread for deletion.
    – tubedogg
    Oct 22, 2014 at 19:54
  • Thomas More, when I use Bluetooth Explorer to change the host controller to the GBU521, I lose my connection to both my keyboard and trackpad, rendering the iMac unusable. The only way to restart the iMac at this point is to power cycle it, and after the restart the Bluetooth controller is reset back to the default. Additionally, Bluetooth Explorer warns that any changes are lost after rebooting.
    – Walter
    Oct 14, 2015 at 10:41

Answer to the original question: Yes. The 'IOGEAR Bluetooth 4.0 USB Micro Adapter (GBU521)' with Chipset: Broadcom 20702A3 is working well in my early 2009 iMac, right out of the box after activating it with Bluetooth Explorer as instructed above @thomas. My Magic Trackpad is working well, as before (had to pair it again, as expected). However, so far Handoff is not supported. I keep investigating if handoff can be enabled using a BT dongle to avoid an invasive fix. Note: despite Host Controller Selector warning, in fact the change IS retained after a restart. Activate the BT dongle only once.

My iMac's System Information reports now after the 'upgrade':

Model Identifier: iMac9,1 (early 2009)

Bluetooth Low Energy Supported: Yes

Handoff Supported: No

Instant Hotspot Supported: No

Manufacturer: Broadcom

Transport: USB

Chipset: 20702A3

Firmware Version: v14 c4096


The mentioned IOGEAR dongle is not shipped worldwide etc not sent to Finland. Google osx bluetooth 4 dongle site:dx.com and you find Ultra-Mini Bluetooth CSR 4.0 USB Dongle Adapter - Black which has been informed to work in older OS X.

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