This tweak aims to increase read speed of both internal and external sd-cards by increasing the buffer size. It should work in any firmware/rom with ROOT privileges, if the rom doesn't support loading scripts from init.d, check the bottom of the post.
Put this script in /etc/init.d with any name, for example 98Sdfix:
#!/system/bin/sh echo "2048" > /sys/devices/virtual/bdi/179:0/read_ahead_kb; echo "2048" > /sys/devices/virtual/bdi/179:16/read_ahead_kb;
Important! the second path 179:16 may vary according external SD size, check the path with a root explorer and adjust the script if needed.
Reboot or run the script in a terminal as root to see the effects
Info: the number 2048 is the new buffer size (original was 128), it can be anything like 256,512,1024,2048,3072,etc. you can use whichever you found best (i recommend Sd Tools to test)
Option 2 (if the above isn't working for you)
#!/system/bin/sh echo "2048" > /sys/devices/platform/mmci-omap-hs.0/mmc_host/mmc1/mmc1:1234/block/mmcblk1/queue/read_ahead_kb; echo "2048" > /sys/devices/platform/mmci-omap-hs.1/mmc_host/mmc0/mmc0:0001/block/mmcblk0/queue/read_ahead_kb;
Note: if the rom doesn't support loading scripts from init.d, it could work anyways using Script manager or any app like it, be sure to check "Run as Root" and 'Run at boot'
Similar Post on http://forum.xda-developers.com/show....php?t=1010807
(it isn't exactly the same since i added external-sd and option 2 is device specific)
I hope it helps
Script attached: unzip and place it in /etc/init.d please check the second path with a root explorer and adjust the script if needed