【512M】Update Debian run in 512M!

First check raspi-config and rpi-update install!
Install rpi-update:
　   $ sudo apt-get update       
　　$ sudo apt-get install ca-certificates 
　　$ sudo apt-get install git-core 
　　$ sudo wget http://goo.gl/1BOfJ -O /usr/bin/rpi-update 
　　$ sudo chmod +x /usr/bin/rpi-update 
　　$ sudo rpi-update 
　　Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS 
　　Performing self-update 
　　Autodetecting memory split 
　　Using ARM/GPU memory split of 192MB/64MB 
　　We're running for the first time 
　　Setting up firmware (this will take a few minutes) 
　　Using SoftFP libraries 
　　/opt/vc/sbin/vcfiled: error while loading shared libraries:libvchiq_arm.so: cannot open shared object file: No such file or directory 
　　If no errors appeared, your firmware was successfully setup 
　　A reboot is needed to activate the new firmware 
　　$ sudo ldconfig 
　　$ sudo rpi-update 
　　Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS 
　　Performing self-update 
　　Autodetecting memory split 
　　Using ARM/GPU memory split of 192MB/64MB 
　　Updating firmware (this will take a few minutes) 
　　Your firmware is already up to date 
　　$ sudo reboot 


Next,
1. raspi-config ----> Update
2. rpi-update
3. sudo sh -c 'cp /root/.rpi-firmware/* /boot'
    sudo rm /boot/arm*_start.elf
4.sudo nano /boot/config.txt
5. In the last line write gpu_mem_512=64.
6.Ctrl+O
7.ctrl+x
8.Reboot
9.$free -m to check is 438.
10.Fast!!!!!!!!!!