Converting WPA2-Enterprise to WPA-Personal on AR300M?

I recently bought AR300M to converting WPA2-Enterprise (in my dorm) to WPA-Personal. However, when I am using WISP mode, it is not giving an option to connect WPA2-enterprise. After doing some research, I found out that I need to upload the firmware. I have download the firmware from here

http://downloads.openwrt.org/releases/18.06.5/targets/ar71xx/generic/openwrt-18.06.5-ar71xx-generic-gl-ar300m-squashfs-sysupgrade.bin

but I am not able to upgrade it. I tried through web UI but it is uploading and I don’t know how to do it via root. I am a newbie in this area. Can someone help me with specific direction on how can connect to WPA2-enterprise? Thanks.

When you choose SSID with WPA2-Enterprise, it should give you a box to enter username and password. Doesn’t the factory firmware work this way?

Actually I am not trying to set up WPA2-enterprise. I want to set up a WPA-PSK but the current available network in my dorm is WPA-enterprise. So I am not able to convert it to WPA-PSK using this router.

AR300M’s firmware can be store in both nor or nand. by default nand. the http://downloads.openwrt.org only privide a nor one.
You can flash nor firmware by uboot web, please refer to this.
https://docs.gl-inet.com/en/3/troubleshooting/debrick/
After flashing nor firmware, the system will still boot from nand, you need extra step to let it boot from nor, please check:
https://docs.gl-inet.com/en/3/hardware/ar300m/#method-1-set-boot-count