AIR-LAP1242AG-C-K9, 1242的瘦AP。以1242AP爲例，1131和1252做法同樣
1、首先準備回退到胖AP的鏡像文件。 我拿到的是一個 “c1240-k9w7-tar.124-10b.JA3.tar”的tar包壓縮文件。
2、準備TFTP的環境。（建議使用Cisco的TFTP工具，其他的方便易用的也行），把目錄指向要升級的鏡像目錄。
TFTP的服務器主機ip地址設置爲10.0.0.2 255.0.0.0 鏡象文件改名爲“c1240-k9w7-tar.default”(IP地址和鏡像文件名這樣改從後面的提示中可以知道是爲什麼)
3、超級終端、控制口連接到AP，以便監控狀態。
4、按住ap上的mode鍵，然後插上電源，稍等一會，出現如下提示
flashfs[0]: 3 files, 2 directories
flashfs[0]: 0 orphaned files, 0 orphaned directories
flashfs[0]: Total bytes: 15998976
flashfs[0]: Bytes used: 1867776
flashfs[0]: Bytes available: 14131200
flashfs[0]: flashfs fsck took 26 seconds.
Base ethernet MAC Address: 00:1d:a1:ff:3c:dc
Initializing ethernet port 0...
Reset ethernet port 0...
Reset done!
ethernet link up, 100 mbps, full-duplex
Ethernet port 0 initialized: link is up
button is pressed, wait for button to be released...
看到上面wait的提示後，鬆開mode鍵
button pressed for 29 seconds
process_config_recovery: set IP address and config to default 10.0.0.1
process_config_recovery: image recovery
image_recovery: Download default IOS tar image tftp://255.255.255.255/c1240-k9w7-tar.default
examining image...
出現上面提示。（從這裏可以看出，在這個狀態下，ap把自己的以太口設置爲10.0.0.1的ip地址，然後去找tftp服務器下的c1240-k9w7-tar.default鏡像文件）
如果上述設置正確的話，就會開始更新了。
5、更新時的屏幕顯示如下：
extracting info (275 bytes)
Image info:
Version Suffix: k9w7-.124-10b.JA3
Image Name: c1240-k9w7-mx.124-10b.JA3
Version Directory: c1240-k9w7-mx.124-10b.JA3
Ios Image Size: 4813312
Total Image Size: 5560832
Image Feature: UNKNOWN
Image Family: C1240
Wireless Switch Management Version: 1.0
Extracting files...
extracting info (275 bytes)
c1240-k9w7-mx.124-10b.JA3/ (directory) 0 (bytes)
............................
extracting c1240-k9w7-mx.124-10b.JA3/info (275 bytes)
extracting info.ver (275 bytes)
Deleting current version...
Deleting flash:/c1240-rcvk9w8-mx...done.
New software image installed in flash:/c1240-k9w7-mx.124-10b.JA3
Configuring system to use new image...done.
Requested system reload in progress...download took about 408 seconds
Loading "flash:/c1240-k9w7-mx.124-10b.JA3/c1240-k9w7-mx.124-10b.JA3"...##################
File "flash:/c1240-k9w7-mx.124-10b.JA3/c1240-k9w7-mx.124-10b.JA3" uncompressed and installed, entry point: 0x3000
executing...
6、到此已經可以了，你等着AP啓動完全。你就可以用console口登陸，和配置交換機一樣配置；或者配置一個IP address
interface BVI1
ip address 192.168.1.5 255.255.255.0
no ip route-cache
!
ip default-gateway 192.168.1.254
此時就可以登陸WEB界面進行配置。Cisco默認用戶密碼爲Cisco