Make sure to save your settings from the GUI in Maint. > Misc. and take all 4 options.
Then burn ISO onto CD then boot and run the Software installer after POST.
Link below provides details on this video though it shows with USB Flash Stick it will work the same w/ CDROM.
It could be that you are on build 4622 and you might try to use the 4786 before going to 5087 or there could be something on volume causing it not to update, try creating a small NAS vol. then run the repair file system from the Extended tools from the Console Screen.
I attempted to update from 6.00up50 b4786 to 6.00up55 b5087 (downloaded iso), but as above I just got stuck at the 'Upload in progress. Please wait.' message. Also, whether related or not, clicking 'check' in 'Update downloader' panel I just get 'Error: Unable to connect to update server'.
Any ideas? I know I can boot of CD, etc and am currently viewing the referenced video.
Check if you have internet access (Gateway, DNS and try to ping a domain name from the Console tools), try run the repair filesystem tool in Extended tools (this will restart system if you have NAS volumes maybe something is going on) - then try once more.
Thanks. No NAS volumes here. But internet access was, of course, the issue for second case. Proxy setting doesn't work for this update downloader? Gave the host full internet access and all fine - downloads the update, ready to be accepted.
But still can't do the local upload (which I don't need now anyway).