Originally Posted by
SeanLee
There is a early checkin available at 945pm for the CX714 flight in august, not sure if it will be opened much earlier though. Also it was reported in the SIN telegram groups that for the transfer T4->T1, it is better to do landside as there were reports of being denied transfer at airside. Also you will need a physical boarding pass. After you are done you can head back to T4 using the airside transfer.
Just reporting what was proven to work, you can try mobile bp or transfer airside and report back any success or hiccups if you like

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There was a post or two in the UA forum that said a mobile boarding pass can enter airside at T3. I tried that myself and it doesn't work.