On the DS of PSoC 4200 family it's indicated that 35-ball WLCSP package is shipped with I^2C Bootloader in Flash.
What this exactly means?
The WLCSP is already supplied with an I2C bootloader. The bootloader is compatible with PSoC Creator bootloadable project. You will be able to program/update your device firmware through a bootloader also. You can refer to WLCSP Package Bootloader Section on Page 9 of the datasheet for further information regarding the same.
I cannot program/debug the device with SWD on pins P3.2 and P3.3 using MiniProg3?
You can still program your device using SWD to program your device.
Like you have rightly pointed out P3.2 and P3.3 are SWDIO and SWDCLK pins respectively as seen in the image.
Hope this helps,
Thanks and Regards,
Rakshith M B
thank you for replying. Yes, was very helpful!