EDIT: This is mostly obsolete now - as it is over 5 years old. It is kept here for historical reference and in case it helps someone with an issue.
This is the collection of information I have posted on Whirlpool's forum for VoIP. As you may or not know, Engin had a marketing promotion that had them selling a version of the Sipura SPA-2000 for $50. The down side of this, was that the unit would only connect to them on Line 1, and be locked out of any other configuration changes on Line 1. Line 2 however, could be used for just about anything you like. For people like me who just wanted to interface a single cordless phone into their own Asterisk system, that was fine.
Then came the problem of firmware upgrades.
The engin boxes will only take config options and upgrade from Engin's own servers. This makes it quite annoying to upgrade your unit if you're not an engin customer. Below is a quick guide on how to upgrade firmware on an engin locked SPA-2000. I will assume that you already have access to your SPA-2000 via a web browser, and not cover the basic information.
In all instructions, substitute x.x.x.x with the IP address of your SPA-2000.
1) Visit http://x.x.x.x/admin/advanced
2) Click on the Settings tab, and write down your DNS Server.
3) Change your DNS Server to: 188.8.131.52 and then click Save Changes.
4) Reboot your SPA-2000 via: http://x.x.x.x/admin/reboot
5) Start the upgrade by entering: http://x.x.x.x/upgrade?http://config.mobileinnovations.com.au/latest.bin
7) Check to see if your SPA-2000 has been updated.
8) Visit http://x.x.x.x/admin/advanced, in the Settings tab, reset your DNS server to the one you wrote down earlier.
9) Reboot your SPA-2000 via: http://x.x.x.x/admin/reboot
Your SPA-2000 should now be running firmware 3.1.3.
If not, check in the Provisioning area of http://x.x.x.x/admin/advanced that the option "Firmware Update" is set to "yes".
EDIT 17/07/2005: Updated to a static 'latest.bin' which will always be the latest firmware verison. Also updated available firmware to 3.1.5