ixpand - not detected after ios 9.3 update

I have a brand new iXpand 32g drive. My ipad is up to date with iOS 9.3.5. My iXpand FW is 4.4.1. It “fails to update” after multiple attempts. ( naturally because I use iPad ) I only have iMac and MacBook computers. There seems to be no MAC update tool, only for Windows which I dont have (naturally)      WHAT GIVES SANDISK??? Any help appreciated