Apollo Lite bricked? Help please.

[Former user]

I was trying to upgrade from Nougat to Oreo.

Updated TWRP to latest. Backed up. Wiped the phone. Installed zips for 8,1 and gapps nano. Phone rebooted - I got the Vernee screen, then for a second or two a yellow circle (I assume this was something to do with the update).

Now the phone is a black screen all the time - sometimes it will vibrate if I try to turn it on and I can sometimes get the boot menu (recovery/fastboot/system) but no which option I choose the phone just goes black again. It does not seem to be charging, I can only get the phone to respond (sometimes) when it is plugged it.

I've been trying to use SPFT to go back to something that works but I have problems - 1. I can seem to get the PC drivers to recognise the phone. 2. The phone will sometimes sense the usb cable from the PC but usually does not. 3. My PC has only USB3 connections.

So, I am wondering if: - I can get the phone to revive using PC software (I'm not familiar with adb/fastboot). - the battery issue to do with the bootloader being broken? - there are any other tricks I can try before binning the phone.