Help using adb sideload to flash update on tecno A7

[itfi]

i know my android might be difficult find in the forum but am stuck in boot without going past boot animation, it occured when i tried to install an app "as system app" the phone blacked out and on restart it hunged on the first screen, i have tried side loading files to sd card but return error: closed
any help?

 

[Hadron]

I assume the phone is rooted if you were doing that. Do you have a custom recovery? If you do then there's a good chance you'll be able to use adb in recovery mode. If you only have a stock recovery adb probably won't work.

If you have a custom recovery but still can't use adb, have you tried adb mounting the sd card?