[PyroNET]

Based on https://vborg.vbsupport.ru/showthread.php?t=81914

# turn the Apache MOD_REWRITE engine on
RewriteEngine On

# this first rule will catch the "blank" entry into the
# Forums directory, taking the user to the main forum page - change as appropriate
RewriteRule ^$ index.php

# this next entry will catch everything else and pass
# it to the member.php engine for processing in
# the "member" section
RewriteRule (^[-_A-Za-z0-9\ ]*$) blog.php?&u=$1

That might work