I have tested latest 1.5.7-core image (without luci) for GL.iNet GL-AR300M-Lite. After reflash it drops me into failsafe mode. And even mounting the root partition and rebooting, doesn't bring the router into normal mode. When reflashing again with "main" branch image (with luci) the router becomes functional in normal mode again.
When in failsafe mode with mounted root partition with 1.5.7-core image there are only 3 files in /etc/config directory: dhcp, dropbear, firewall.
Below is the hash of the core squashfs-sysupgrade file.
echo 'a9cb8f1144f139bad2183073b3aff11d8e287349c8fd3cfe53f88dcc27d972f4 librecmc-ath79-generic-glinet_gl-ar300m-lite-squashfs-sysupgrade.bin' | sha256sum -c
The core images for ath79 have been rebuilt.
Today I tried to wget https://librecmc.org/librecmc/downloads/snapshots/v1.5.7-core/targets/ath79/generic/librecmc-ath79-generic-glinet_gl-ar300m-lite-squashfs-sysupgrade.bin
As you can see, the hash is the same as previously. I think the image didn't see the change.