同一块板子，使用spi启动，网络是正常的，dhcp能正常获取，能正常通信
使用tf卡启动，就不能发现网口，请问什么原因

tf卡启动时显示
Starting network: ifconfig: SIOCGIFFLAGS: No such device
ifconfig: SIOCSIFADDR: No such device
ifconfig: SIOCGIFFLAGS: No such device
udhcpc: SIOCGIFINDEX: No such device
FAIL

ifconfig -a 显示：

ifconfig -a

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)