Core dump - WLAN init

[dabal221]

Hello,
there is a strange issue. Yesterday I could normally create an object of class WLAN().
Today, execution of lines:

import network

wlan = network.WLAN()

cause Core Dump Issue. It seems like this:

PC      : 0x40140101  PS      : 0x00060c30  A0      : 0x8013e810  A1      : 0x3ffb5670  
A2      : 0x00000020  A3      : 0x3ffcbc70  A4      : 0x3ffcbba8  A5      : 0x00000080  
A6      : 0x0000001b  A7      : 0x600050dc  A8      : 0x3ffae0c4  A9      : 0x3ffb5650  
A10     : 0x4013fd04  A11     : 0x00000000  A12     : 0x00000020  A13     : 0xffffffe8  
A14     : 0xffffffdf  A15     : 0x3ffcbba8  SAR     : 0x00000007  EXCCAUSE: 0x00000000  
EXCVADDR: 0x00000000  LBEG    : 0x4013e7c4  LEND    : 0x4013e7ce  LCOUNT  : 0x00000000  

ELF file SHA256: 0000000000000000000000000000000000000000000000000000000000000000

Backtrace: 0x40140101:0x3ffb5670 0x4013e80d:0x3ffb56b0 0x4013f24d:0x3ffb56f0 0x4013f72c:0x3ffb5710 0x40167058:0x3ffb57d0 0x4016708d:0x3ffb57f0 0x401671dc:0x3ffb5810 0x401295b4:0x3ffb5840 0x401296a5:0x3ffb5870 0x4012999e:0x3ffb58a0 0x40125836:0x3ffb58d0 0x4014a0fb:0x3ffb58f0

I use 1.20.2.rc3 release.

Does anyone have similar problem? Please help.