BLUENRG-1 locks after flashing

[MRey.1]

I am testing a custom board trying to use BLUENRG-1 as a coprocessor, but when I flash the chip (using Keil, Atollic or BlueNRG-1 ST-Link Utility) with ST-Link/V2 tool, with the SWD port, the chip locks and I am unable to access the chip again, regardless of the application I use.

I tried flashing the DTM example project, in BlueNRG-1_2 development kit, but that is the result. Any ideas about what could be causing this issue?