[U-Boot] some questions about u-boot

[li guohu]

Hello, I am a newbie in the world of u-boot. There are three questions when I am using the u-boot. Can someone help me?
 
1. Before the u-boot enter the command line, some error like "Error: environment overflow " happens. The space in the ram used to save the environment variables are 0x2000. I think this is enough. I set this space in the head file like this: #define CONFIG_SYS_ENV_SIZE 0x2000. 
 
2. Are there any commands in the u-boot to read and write the FRAM? 
 
3. After the u-boot enter the command line, I enter the command "mii info". But nothing appears. If I enter the command "mii read 0x1 0x1", I can only see 0xFFFF. If I ping some address, I can see 32 lines if I use the "mii info" then. The address of the PHY is 0x1. 
 
I have put a file in the following. It records all the words printed by the u-boot.
Thanks.
 
 
U-Boot 2009.03 (Apr 05 2012 - 19:23:09) MPC512X
CPU:   MPC5125 rev. 1.0, Core e300c4 at 393.216 MHz, CSB at 196.608 MHz
board: mpc5125_mpu
I2C:   ready
DRAM:  256 MB
Now running in RAM - U-Boot at: 0ff14000
NAND:  256 MiB
In:    serial
Out:   serial
Err:   serial
## Error: environment overflow, "stdin" deleted
## Error: environment overflow, "stdout" deleted
## Error: environment overflow, "stderr" deleted
Net:   ## Error: environment overflow, "ethact" deleted
FEC ETHERNET## Error: environment overflow, "ethact" deleted

Type "run flash_nfs" to mount root filesystem over NFS
Hit any key to stop autoboot:  2  0 
=> 
=> mii info
=> ping 169.254.9.  89.102
## Error: environment overflow, "ethact" deleted
Using FEC ETHERNET device
FEC ETHERNET tbd status: 0x0000
FEC ETHERNET tbd status: 0x0000
ping failed; host 169.254.89.102 is not alive
=> mii info
PHY 0x00: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x01: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x02: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x03: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x04: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x05: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x06: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x07: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x08: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x09: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x0A: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x0B: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x0C: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x0D: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x0E: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x0F: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x10: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x11: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x12: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x13: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x14: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x15: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x16: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x17: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x18: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x19: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x1A: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x1B: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x1C: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x1D: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x1E: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
PHY 0x1F: OUI = 0x0000, Model = 0x00, Rev = 0x00,  10baseT, HDX
=>