mkdir /firmware
cd /firmware
wget https://fw.gl-inet.com/download/RM520NGLAAR03A03M4G_BETA_20240521C_01.200.01.200.zip
unzip RM520NGLAAR03A03M4G_BETA_20240521C_01.200.01.200.zip -d RM520NGLAAR03A03M4G_BETA_20240521C_01.200.01.200
QFirehose -f RM520NGLAAR03A03M4G_BETA_20240521C_01.200.01.200
reboot
try upgrade