I experienced the same issue with mine but after spending a day trying to recover it I was finally successful.
First off none of the published stable builds will flash successfully.... meaning uboot reports a successful flash but after the device reboots it's dead.
Then I successfully used uboot to load the latest openwrt SNAPSHOT and had the device back up and running. Link: https://downloads.openwrt.org/snapshots/targets/mediatek/filogic/openwrt-mediatek-filogic-glinet_gl-mt2500-squashfs-sysupgrade.bin
Then I tried the latest 4.7.0 beta 9 and was then back in business with gl.inet based firmware. Link: https://fw.gl-inet.com/firmware/mt2500/testing/openwrt-mt2500-4.7.0-1125-1732545389.bin
I did notice that if I tried to load any of the official stable gl.inet images via openwrt that there is SOC cpu target mismatch error. Seems that the official stable gl inet releases are not configured properly for the appropriate SOC target.