Kernel upgrade to fix SDHC performance issues

[MatB]

Hi, i've got my plug 2 days ago, so please pardon my lack of experience.
The rootfs resides on a Sandisk extreme III, but the I/O performance is very poor; I'm running the standard kernel 2.6.22.18, and i get 3.5MB/s and 7.3MB/s in write and read operations, respectively.
I did not upgrade uboot (yet) so i'm still running the stock kernel.
I read in the forum that there are some patches to fix the performance issue; are these patches already included in the 2.6.30.1 kernel from cbxbiker61?
I'd like to keep my current root fs, if possibile. What is the easiest and safest way to upgrade the kernel? Should i flash the uimage, boot it from network or from a USB dongle?

[MatB]

*bump*

[joosty]

Congrats with the plug, I got mine last monday

My situation is a bit different from yours, but I'd be interested in the answer also.

I'm running Debian on an SD card (followed http://www.cyrius.com/debian/kirkwood/sheevaplug/), and the kernel and initrd are both on the SD card and booted using an upgraded uboot. First thing I did after getting the plug was running the alpha 6 installer, and after that the Debian install guide. Now I can easily switch kernels by using the standard debian proces. No SD performance problems here. (I do have big problems when I attach a usb hub between the plug port and external hard drive, but I'm working on that )

Anyway, I'm also wondering how to install the "cbxbiker61" kernels. For example, it delivers a uImage, but in my Debian install a kernel is always accompanied by its own initrd (or, after uboot gzip, uInitrd), no idea yet how to generate that, unless there's an easy way to 'gunzip' the uImage.