I believe it should work with that recovery. It is the one found here: LEM T Reviews and FAQs - #64 by iscle, right?
what new scatter file? The scatter file can be the same as before
Is it so that the name originally didn’t have .img in it and you added .img to the name when you changed it? If that is the case it might be the reason why it’s not working
I have also prepared two patched boot images you can try if you want (after flashing it together with twrp you have to use the adb command “adb reboot recovery” in order to boot to twrp):