4028EE - SIP + Asterisk?

[Awoo]

Hi!

I've recently got my hands on a few used enterprise phones, which I'm trying to use as SIP devices with Asterisk. Thanks to the materials on this forum, I was able to get a 4018 switched to SIP mode and using DHCP + TFTP to talk to Asterisk.

The new challenge is the 4028. I'm able to access the i + # menu just fine, but the device does a beep when trying to switch Run Mode from NOE to SIP.
With my current setup, the phone connects to my TFTP server, but only requests for a lanpbx.cfg file. I've tried putting the following file on the server, but the device only shows a bad file content error message.

Code: Select all

> cat lanpbx.cfg
APPLICATION_TYPE=APPL_SIP

Is there a way to get this model to do SIP? A firmware update, perhaps? Please assist, I'd hate to throw such a well-made phone away

Device Software Versions:
Main: NOE 4.33.40
Application: NOE 4.33.40
Data: NOE 4.33.40
Load: 4.33.40
Boot: 4.10.01
L10n: none
CustN: none