Can't Read SD Card Anymore / Can't Turn It On?!

I am sorry all my suggestions did not help you. And sorry for your Clip Sport troubles.

I have not tried FW 1.29 for myself (still using 1.28 from Sept. 2015).  FW 1.28 is no longer provided by SanDisk website.

Before you abandon your Clip Sport maybe try to install FirmWare 1.27 into the root folder of your Clip Sport.

FW 1.27 is still available for download on the SanDisk support website.

      http://forums.sandisk.com/t5/SanDisk-Clip-Sport/SanDisk-Clip-Sport-Firmware-1-27-released/td-p/340602

Follow the installation instructions using the manual update method after you download the “hex” file.

Best Wishes.