When building OpenWRT Kamikaze 8.09.2 for the DSL502T there are a number of mobiles included by default that are important if you are using the device as a modem but unnecessary if you plan to use the device as an appliance.

After some playing I have found the following modules can be excluded:

Kernel Modules = kmod-sangam-atm-annex-a, kmod-ppp, kmod-pppoa, kmod-pppoe, kmod-ocx

In my configuration the difference in after boot memory usage is as follows:

Before

Mem: 10268K used, 2492K free, 0K shrd, 1300K buff, 4168K cached

Modules

Module                  Size  Used by    Not tainted
tiatm                 151008  0
acx                   136704  0
nf_nat_tftp             1088  0
nf_conntrack_tftp       3760  1 nf_nat_tftp
nf_nat_irc              1856  0
nf_conntrack_irc        4768  1 nf_nat_irc
nf_nat_ftp              2432  0
nf_conntrack_ftp        6880  1 nf_nat_ftp
ipt_MASQUERADE          2080  0
iptable_nat             4240  0
nf_nat                 14624  5 nf_nat_tftp,nf_nat_irc,nf_nat_ftp,ipt_MASQUERADE,iptable_nat
xt_state                1600  0
nf_conntrack_ipv4      12064  3 iptable_nat,nf_nat
nf_conntrack           46592  11 pppoatm                 4320  0
ipt_REJECT              2976  0
xt_TCPMSS               3136  0
ipt_LOG                 6720  0
xt_multiport            2528  0
xt_mac                  1312  0
xt_limit                2016  0
iptable_mangle          2080  0
iptable_filter          2080  0
ip_tables              10064  3 iptable_nat,iptable_mangle,iptable_filter
xt_tcpudp               2624  0
x_tables               11504  11 ppp_async              10944  0
ppp_generic            26080  2 pppoatm,ppp_async
slhc                    5952  1 ppp_generic
crc_ccitt               1440  1 ppp_async
br2684                  7920  0
atm                    48912  3 tiatm,pppoatm,br2684

After

Mem: 7628K used, 5132K free, 0K shrd, 964K buff, 3180K cached

Modules

Module                  Size  Used by    Not tainted
acx                   136704  0
gpio_dev                3184  0
br2684                  7920  0
atm                    48912  1 br2684