1. 先確定有足夠的RAM和ROM(flash)空間. 參考Cisco.com的release note.

2. Upgrade流程:6.3(5)->7.0(1)->7.2(4)->8.0(4) or 6.3(5)->7.2(4)->8.0(4)
    試過 6.3(5)->8.0(4) ok, but多數人不建議這樣做
    software最新版: pix804-28 + asdm615

3. 常用command:
    copy tftp flash: 將bin檔從tftp下載到flash中
    wr erase: 把目前所有config清除
    wr mem: save change
    reload: reboot PIX
    sh flash: 看flash內的使用狀況
    sh ver: 看系統整體狀況
    sh int: 看網路卡狀況
    hostname PIX1:改hostname
    copy tftp startup (copy startup tftp): restore(backup) config from(to) tftp
    copy tftp running (copy running tftp): restore(backup) running config from(to) tftp

4. 準備 TFTP server (最好用XP並turn-off firewall,Windows 7會擋traffic)
    連到server的port要有IP
    pix#conf t
    pix(config)#int eth1
    pix(config-if)#ip addr 192.186.10.200
    pix(config-if)#no shutdown

5. Upgrade from Monitor mode(無法用copy tftp指令時才用,開機後按ESC進入Monitor mode):
    monitor>interface 1
    monitor>address 192.168.10.200 (PIX eth1 的IP)
    monitor>server 192.168.10.5 (tftp server IP)
    monitor>file pix804.bin
    monitor>ping 192.168.10.5 (先確定可以ping到tftp server)
    monitor>tftp

6. Upgrade using TFTP command:
    copy tftp flash 然後回答server IP, server filename, 存到flash要用的filename
    如果發生not enough space, 用sh flash檢查. 用del先刪掉不要的file.
    pix(config)#del pix724.bin
    舊的boot commmand要先拿掉
    pix(config)#no boot system flash:pix724.bin
    copy完成後下boot指定開機時要讀的檔:
    pix(config)#boot system flash:pix804.bin   
7. 確定flash有足夠space,同樣用copy tftp flash下載asdm
    啓用asdm:
    pix(config)#asdm image flash:asdm-615.bin
    pix(config)#http server enable
    允許內部IP連上asdm server
    pix(config)#http 192.168.10.0 255.255.255.0 inside
    設定asdm的username和password
    pix(config)#username admin password pass1234
    用browser下載ASDM
    https://192.168.10.200

**記得下wr mem儲存設定