I have secondhand Vodafone Smart Tab 4G. It seems to me that previous owner messed something up.
The device boots normally but I cannot enter either bootloader, fastboot, or recovery. I have tried HW combinations, RebootManager software, and ADB commands. I would like to restore the device to factory defaults, but I have no idea how to do that.
I can connect by ADB:
~ $ adb devices List of devices attached 1b54ef6a device
But if I try either
adb reboot bootloader, or
adb reboot recovery, the device hangs on "Powered by Android" logo. If I try
adb reboot fastboot it just normally reboots.
Trying to restore factory defaults from settings or running system update, the device reboots and hangs on "Powered by Android" logo.
Also the device is rooted.