Have you tried to set the pool through Innomonitor software?
You can download innomonitor from here
https://www.innosilicon.com/html/support_en/tool.htmlThen change the pool using that software. If not work it might need to flash via TF/SD card.
Do you have any idea if what t2th+ control board is?
Check the control board physically if it's the g9 or the g19 control board.
If it g19 then try to flash it through SD card you can download the boot image under "Innosilicon A4+ Miner" in their
download page.