If your device is a "repack" (specifically a third-party replica or non-official assembly), the hardware keys might trigger a different bootloader menu:
Stick to:
If your phone is turned on and you have enabled in Developer Options, you can boot into this mode via a PC. how to open fastboot mode on samsung galaxy a7 repack
(older models) or Volume Down + Volume Up + USB Cable (newer models). How to Open Fastboot Mode on Samsung Galaxy
heimdall detect or check lsusb on Linux to confirm connection.Type the following command and hit Enter: adb reboot bootloader Turn off your Samsung Galaxy A7 completely