PC：Personal Computer（这里用的Win7）
CM：Cable MODEM（芯片：BCM93349DCM）
一、预置条件
1、PC上已安装TFTP Server，比如tftpd32；
2、PC上已安装USB转串口驱动，可以通过串口与CM通信；
3、PC上已有编译好的CM Fireware。
二、网络连接
1、PC与CM分别通过串口和网口相连；
2、手工设置PC固定IP，比如192.168.100.2；
3、在PC端打开tftpd32，设置好路径和服务器接口。
三、升级过程
通过串口操作，有4步：设置IP建立通信--使用TFTP上传Fireware--升级--重启。
粗体蓝字是要输入的信息，不需要修改的直接回车继续。
Enter '1', '2', or 'p' within 2 seconds or take default...pBoard IP Address [10.3.45.189]: 192.168.100.1Board IP Mask [255.255.255.0]: Board IP Gateway [10.3.45.254]: 192.168.100.2Board MAC Address [00:10:18:ff:ff:ff]:Internal/External phy? (e/i)[i]Init EMAC...Autonegotiation... successfulMain Menu:==========b) Boot from flashg) Download and run from RAMd) Download and save to flashe) Erase flash sectorm) Set modes) Store bootloader parameters to flashi) Re-init ethernetr) Read memoryw) Write memoryj) Jump to arbitrary addressz) ResetdTFTP Get SelectedBoard TFTP Server IP Address [10.3.45.42]: 192.168.100.2Enter filename [DVB-C8000BG_GD_cm.bin]: ecram_sto.binDestination: a0b00000Starting TFTP of ecram_sto.bin from 192.168.100.2Getting ecram_sto.bin using octet modeInit EMAC...Autonegotiation... successfulTftp timeout.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Tftp completeReceived 1021660 bytesImage 3 Program Header:Signature: 3349Control: 0005Major Rev: 0003Minor Rev: 0000Build Time: 2015/3/20 01:57:01 ZFile Length: 1021568 bytesLoad Address: 80010000Filename: ecram_sto.binHCS: 342eCRC: 9556335eCRC VerifiedDestination image0 = bootloader1/2 = CM image3 = specify flash offset4 = asymmetric image 25 = alternate image 1 (SPI flash block 1)(0-3)[2]: 1Image 1 Program Header:Signature: 3349Control: 0005Major Rev: 0003Minor Rev: 0000Build Time: 2015/3/19 02:15:36 ZFile Length: 1021358 bytesLoad Address: 80010000Filename: ecram_sto.binHCS: 6267CRC: fbb8d0faFound image 1 at offset 20000Erasing before writing at offset 20000...SpiFlashWrite: Writing flash at 00020000Store parameters to flash? [n]Main Menu:==========b) Boot from flashg) Download and run from RAMd) Download and save to flashe) Erase flash sectorm) Set modes) Store bootloader parameters to flashi) Re-init ethernetr) Read memoryw) Write memoryj) Jump to arbitrary addressz) Resetw) Write memoryj) Jump to arbitrary addressz) Resetz
升级成功并重启。
四、严重注意
升级时CM和PC的IP都是手动配置！
CM IP = Board IPPC IP = Board TFTP Server IP因为CM启动时按p进入升级模式，就不会再启动DHCP模块了，所以CM不会通过DHCP给PC分配IP地址。