try this link
Firmware Android 5 Lollipop PhonePad G510 - Downloads - Forum AVRMagazine.com Android 5 lollipop
or this
Firmware PhonePad G510 - Downloads - Forum AVRMagazine.com Android4
iam tired login to this site to give you directlink but you most register to this site and download your firmware
iam sorry for english lang but my computer not support Arabic languge
but you need login in site