Help! Boot Loop or Complete Brick? :(
So a friend recently bought this spanish voxter tab 97 IPS (16GB) and after a few days of usage and several attempt to install a custom ROM, the tablet stopped booting. According to him, he tried loading a "compatibility bla bla bla.zip" file with CMW which I really do not know what it is, and since he did the installation, the tab stopped booting into system. Every time it's turned on, it just stops at the boot screen and nothing more. Although before this, he had installed a custom recovery and had also done a Nandroid backup with the recovery. However, what baffles me is, CMW is no longer accessible through the normal "power + volume up" key combo and I'm quite unsure of how to boot into fastboot.
That aside, I tried booting into recovery with adb because apparently, adb recognizes the device whenever it's stuck at boot screen, this also failed, neither did rebooting into fastboot via adb work. All I need to know is if this device is totally bricked, or if there's still something I can do. If there's any, I really would appreciate every help offered. Thanks..