I designed a PCB that contains a step up regulator circuit with TPS61030. The original intention was to convert 2.5V to 5V. However, after assembling the board I found a strange behavior of the circuit. The output voltage is always little smaller than the input voltage by 0.2V or so. This test was done without loads. This problem was found in two identical boards.
I carefully checked all solder joints in the board and removed residual flux and IPA again and again. Thus the problem might not be caused by bad soldering. I tried to find problem from my schematic and layout, but to me they look okay. It would be very appreciated, if one suggests the cause.
The followings are my schematic and layout.
