I have iPhone 3G / ver. 2.2 and baseband 02.28.00

I jailbreaked it and unlocked it. It worked perfectly for 2 days - i was making and receiving calls. And suddenly the phone displayed NO SIM, No Sim Installed.

I switched with different sim cards, which all work with other phones and are from different operators. I also restored the phone with iTunes (firmware 2.2) and then jailbreaked it again.

It didn't fixed it.

Now I'm wondering is it my iphone modem working ( hardware problem ).

I get this from my log-bb-live-stats file :

2:50:05 -0800 ST [rm] crash: state=Initialized
2:50:05 -0800 ST [rm] reset: reason=modem reset;uptime=8357;count=1;callactive=false;pdpacti ve=false;rat=3
2:50:37 -0800 ST [rm] crash: state=Initialized
2:50:38 -0800 ST [rm] reset: reason=modem reset;uptime=31;count=2;callactive=false;pdpactive =false;rat=3
2:52:19 -0800 ST [rm] crash: state=Initialized
2:52:19 -0800 ST [rm] reset: reason=modem reset;uptime=100;count=3;callactive=false;pdpactiv e=false;rat=3
2:54:10 -0800 ST [rm] crash: state=Initialized
2:54:10 -0800 ST [rm] reset: reason=modem reset;uptime=110;count=4;callactive=false;pdpactiv e=false;rat=3

So my question is :

How to check is my hardware baseband modem functioning properly through ssh or any available software.

10x in advance