Both work great under OpenWRT 10.03.1 but not under 12.09 which feels slower. While 14.07 feels snappier, it consumes all the 4MB of flash memory.
Well, today I've got some time to build a lightweight OpenWRT 14.07 for both DSL-524T and DSL-G624T.
The installation steps are documented for both.
As reference, these are the steps I did for DLink G624T.
# under root or using sudo
echo 0 > /proc/sys/net/ipv4/tcp_frto
# just a second or two after the router is powered up
ftp -n 192.168.1.199
# adam2 as a password also
quote "SETENV mtd1,0x90010000,0x903f0000"
quote MEDIA FLSH
put "openwrt-ar7-generic-squashfs.bin" "openwrt-ar7-generic-squashfs.bin mtd1"
Notes: While both DSL-524T and DSL-G624T ran OK under 14.07 you should go easy with LuCi as 16MB of ram is really the minimum requirement. After setting things up consider disabling LuCi for better performance. A /etc/init.d/luci disable would suffice.
A USB-to-UART (USB-to-TTL) cable is not necessary but would be helpful in case you want to know what happens while flashing it or setting it up.
|Red is GND, Green is RX and White is TX|
Usually you need to setup CuteCom or Putty to 38400 baud, 8 bit, no parity, 1 stop bit. Serial (/dev/ttyUSB0)