AR18/AR28在系统启动时按ctrl＋B进入bootrom menu后，按ctrl＋F即可格式化flash，当然会有一个Y/N的提示，避免误操作；AR46则不同，系统启动时，按ctrl＋B进入main-bootrom menu后，需要按ctrl＋Z进入隐含子菜单，具体操作如下：

=====================<MAIN-BOOTROM MENU>=====================                   

| <1> Boot With Default Mode                                |                  

| <2> Boot From Flash                                       |                  

| <3> Enter Serial SubMenu                                  |                  

| <4> Enter Ethernet SubMenu                                |                  

| <5> Boot File Control                                     |                  

| <6> Modify Bootrom Password                               |                  

| <7> Reset Console Authentication                          |                  

| <8> Ignore System Configuration                           |                  

| <9> Enter Debugging Environment                           |                  

| <a> Reboot                                                |                  

=============================================================                  

Enter your choice(1-a):     -----------------------按CTRL-Z进入隐含子菜单  

Hidden menu...                                                                 

======================<HIDDEN SUB-MENU>======================                  

| <1> Flash Operateion                                      |                  

| <2> Delete File From Flash                                |                  

| <3> Disable Config Password                               |                  

| <4> Upgrade Small BootRom                                 |                  

| <5> Upgrade South-Bridge Logic                            |                  

| <6> Exit To Main Menu                                     |                  

=============================================================                  

Enter your choice(1-6): 1    --------------------按1进入flash操作菜单

Flash miscellious test.                                                                                                                                     

======================<Flash Operation>======================                  

|Note: System will boot with only flash test with flash     |                  

|      test flag set,no VRP programme running any more,     |                  

|      choose <show flash test result> to see the result.   |                  

|-----------------------------------------------------------|                  

| <1> Erease flash                                          |                  

| <2> Set flash test flag                                   |                  

| <3> Clean flash test flag                                 |                  

| <4> Show flash test result                                |                  

| <5> Set flash test delay in hours                         |                  

| <6> Return to main hidden menu                            |                  

=============================================================                  

Enter Your Choice(1-6):1   --------------------按1格式化FLASH