PROBLEM WITH NEXUS 7 2012

I have accedently delete particion and i read thet this devace need special tool for backup

how can i restore particion

Since this is a Nexus device you can typically download the firmware from Google’s Developer Site as a “factory image” and reflash it following their directions. https://developers.google.com/android/images#nakasi

See also, https://forums.androidcentral.com/google-nexus-7-2012-rooting-roms-hacks/191477-guide-nexus-7-factory-image-restore.html but read it very carefully as they cover all 4 Nexus 7 models (2012 wifi/GSM and 2013 wifi/LTE).