I downloaded the firmware firmware from the url http://daemonizer.de/prism54/prism54-fw/fw-usb/2.13.24.0.lm87.arm
I renamed the file 2.13.24.0.lm87.arm to isl3887usb
Then copied to the file isl3887usb to the pc into the folder /lib/firmware/
I replugged the usb dongle and working fine.
Thank you, Jeff, worked for me.
I downloaded the firmware firmware from the url http:// daemonizer. de/prism54/ prism54- fw/fw-usb/ 2.13.24. 0.lm87. arm
I renamed the file 2.13.24.0.lm87.arm to isl3887usb
Then copied to the file isl3887usb to the pc into the folder /lib/firmware/
I replugged the usb dongle and working fine.