Hi,
I'm new to linux, and I've just installed Mandrake 9.2, but because of some ATM-'bug' in the kernel (2.4.22), i have to downgrade it to 2.4.20 to get my adsl modem to work. First of all, how can i do this (i heard there are some good kernel upgrade/downgrade tools , but i don't know what to use

), and second, will this have any negative effects on stability or performance?
Thanks in advance,
Pleun