LouisTong,
I am probably putting my head on a block with Dell Support, but according to my experience of the problem, the bricking of the XPS13 was caused by a combination of Windows 8 (pre-installed), the A07 BIOS version and a Windows Update that went through on February 12/13 2013. This combination corrupted the BIOS ability to boot into Windows (or any device, including USB flash disks and required a motherboard replacement. After a motherboard replacement and an immediate A08 BIOS upgrade, some people had *some* success. I did not and was not able to get the factory-installed Windows 8 to start or restore. I elected to downgrade to WIndows 7 SP1 and the XP 13 has been running faultlessly since then, and is just as fast and responsive. (I am typing this message using it)
Local Dell support was good once I made noises with Enterprise Support. The world-wide shortage of the XP-13 motherboard was a problem, in my opinion caused by this issue, but Dell have not gone as far as to declare a "recall" of the XPS-13 to investigate the BIOS corruption issue.