Slow NAND programming

Hello,

I want to write a bin file to my NAND memory (256MiB 8-bit).

My configuration: Ubuntu 11.04, Amonteg JTAG key (6MHz), openOCD 0.4, CPU - S3C2412.

Writing works but really slow - for 100kb bin file it takes 10 minutes.

What is reason of this issue, how to improve this?

Best regards,