1、出现故障的原因：
A、通过手动更换镜像导致
Boot Loader Menu
- Run primary image (7.0.220.0) - Active
- Run backup image (7.0.220.0)
- Change active boot image
- Clear configuration
- Format FLASH Drive
-
Manually update images
Enter selection: 6
B、版本之间不能直接升级导致
C、Flash被erase了
故障现象：
.......
loading primary image(Bad image type)
Launching...
Launching images...
2、解决方法：
开机ESC，选6：Manually update images；
注意：该模式下无法解密.aes文件。需要单独加载RTOS进行升级然后进入系统升级。
所需文件，如下示例（可能版本有不同）：
enter filename for RTOS update: AS5500RTOS-7.0.250.0RTOS
Enter filename for FP update: AS5500caviummain-7.0.250.0
获取方式：通过思科官方获取（联系思科TAC支持，获取）。
另：该云盘下有7.0.250.0的RTOS
http://pan.baidu.com/s/1ntqPeh7
3、安装细节：
Boot Loader Menu
============================================================
-
Run primary image (Image not found) - Active
-
Run backup image (Image not found) This shows that there are no valid images in either Primary or Secondary partition, and that the system is configured to boot from Primary.
-
Change active boot image
-
Clear configuration
-
Format FLASH Drive
- Manually update images
Enter selection: 6
Launching...
Launching images...
init started: BusyBox v1.6.0 (2009-02-03 04:56:32 EST) multi-call binary
Mount failed for selinuxfs on /selinux: No such file or directory
starting pid 655, tty '': '/etc/init.d/rcS'
Use DHCP for ip configuration (Y/n)? n
Enter switch IP address: 192.168.1.100
By "switch", the boot loader means WLCEnter switch netmask: 255.255.255.0
Enter switch gateway: 192.168.1.1
Enter TFTP server IP address: 192.168.5.157
You have entered:
IP Address : 192.168.1.100
Netmask : 255.255.255.0
Gateway : 192.168.1.1
Server Ip Addr : 192.168.5.157Is this correct(y/N)? y
!!! WARNING updating using .aes or unapproved files will disable this unit !!!
Do you want to update RTOS (y/N)? y
Do you want to update Primary Or Secondary Image (P/s)? P
Enter filename for RTOS update: AS_5500_RTOS-7.0.250.0RTOS update Done
Enter filename for FP update: AS_5500_cavium_main-7.0.250.0
Depending on your WLC model / boot loader version, you may not be prompted for FP update
FP update DoneDo you want to update an AP image (y/N)? N
AP Images Not UpdatedDone.
Restarting...
Restarting system.
WLCNG Boot Loader Version 1.0.15 (Built on Nov 23 2010 at 07:51:36 by cisco)
Board Revision 0.0 (SN: PSJ143806NP, Type: AIR-CT2504-K9)
(W)Verifying boot loader integrity...
OK.