For this problem, try a more specific command as part of a structured routine.
01) start 14A238x
02) ignore App Store
03) unmount all volumes except the 14A238x volume from which you started
04) in Terminal,
Code:
sudo softwareupdate -v -d "OS X 10.10 Update-1.0" ; open /Library/Updates
05) after Terminal opens the window in Finder, browse to the update .pkg
06) tag then open the .pkg and follow the routine that's given in Installer.app
07) when Installer prompts you to restart, do so
08) if it becomes necessary to
force a restart, then reuse the .pkg that you tagged at step (06)
09) with 14A261i running, proceed in a similar way ...
10) ignore App Store
11) unmount all volumes except the 14A261i volume from which you started
12) in Terminal,
Code:
sudo softwareupdate -v -d "OS X 10.10 Update-1.0" ; open /Library/Updates
13) after Terminal opens the window in Finder, browse to the non-tagged update .pkg
14) to the non-tagged update .pkg, apply a unique tag
15) open the .pkg and follow the routine that's given in Installer.app
16) when Installer prompts you to restart, do so
17) if it becomes necessary to
force a restart, then reuse the .pkg that you tagged at step (14)