Hi Brian,
it is very unfurtunate that this open source plugin (GNU ARM Eclipse) for some reasons breaks the Segger J-Link debugging functionality. So I appologize for that.
KDS is based on many open source projects, and yes, sometimes things unfortunately are breaking.
I have to say that in the past the GNU ARM Eclipse plugins were outstanding and rock solid.
As for the list of update sites: each plugin can add its own update sites, the ones provided by Freescale are:
Freescale KDS Update Site - http://freescale.com/lgfiles/updates/Eclipse/KDS
and the local one from the Kinetis SDK:
KDS v1.2 Update - jar:file:/C:/Freescale/KSDK_1.2.0/tools/eclipse_update/KSDK_1.2.0_Eclipse_Update.zip!/
So the two above are the 'official' ones, where Freescale extensions and plugins are provided.
Beside of that, other plugins in KDS provide their update sites, including the following:
P&E provides this update site:
PEMicro - http://www.pemicro.com/eclipse/updates
From Eclipse.org, there are the following update sites:
Luna - http://download.eclipse.org/releases/luna
And the GNU ARM Eclipse one (GNU and GDB intergration):
GNU ARM Eclipse Plug-ins - http://gnuarmeclipse.sourceforge.net/updates
I have not had issues in the past to update using these update sites (including others I use in my Eclipse installation). But as always there could be something going bad, I usually make a copy of my Eclipse/installation folder before making an update. Just in case...
I appologize again for the issue, and hope this helps,
Erich