When you first power the 120 on you should see "briefly" something like this and at the bottom "To change any of this, press any key within 2 seconds".
If you dont see the bottom part or it wont let you in when you press a key then I think you have the update.
You need to reflash the mxchip with preupdate 120 flash from downloads.
BCM3345
134ce7865
Boot Code SW Version 3.11.1
BCM3345 Ambit
S12ce7865Detect MXIC MX219LV160B Flash
Ambit Cable Modem Console Management
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NETWORK INTERFACE PARAMETERS:
IP address on LAN is 192.168.100.1
LAN interface's subnet mask is 255.255.255.0
HARDWARE PARAMETERS:
This board's Ethernet hardware address is **:**:**:**:**:**
This board's USB Interface hardware address is **:**:**:**:**:**
CABLE MODEM APPLICATION PARAMETERS:
IP address of the TFTP host is [62.253.189.101]
The file to download and start is ntlhm100_ntl0002.cpr
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To change any of this, press any key within 2 seconds