Our migration from 5.3sp1 to 2011sp1 will happen for period of 2-3 months, but content will be added on production during that time in tridion 5.3sp1. 
After the migration activities we will have migrated system on 2011sp1,  

But now i want to migrate new content from production(which is still in 5.3) to upgraded DB.

Content porter version 2.3(currently being used in 5.3sp1 ) is not supported in 2011.

What would be the best approach for this?


Question: Hanging boot and cannot boot to disk
Answer: Another option would be to boot from a usb stick, if your mobo supports it. Most major linux distributions support booting from usb. Also, several recovery tools are available and capable of usb booting.