Unable to boot ESP32 after ESP32.enableWifi(false)

I wanted to turn wifi off on my board to check out how much memory it would release. Unfortunatly I trap into infinite trying to boot. Firstly I get:

>ESP32.enableWifi(false)
Erasing saved code.
Done!
ets Jun  8 2016 00:22:57
rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0018,len:4
load:0x3fff001c,len:2984
load:0x40078000,len:10700
load:0x40080400,len:5236
entry 0x40080658
E (562) psram: PSRAM ID read error: 0xffffffff
E (562) spiram: SPI RAM enabled but initialization failed. Bailing out.
E (562) spiram: SPI RAM not initialized

Then:

Guru Meditation Error: Core  0 panic'ed (LoadProhibited). Exception was unhandled.
Core 0 register dump:
PC      : 0x401c501c  PS      : 0x00060430  A0      : 0x801b677b  A1      : 0x3ffea1b0
A2      : 0x3ffd0568  A3      : 0x3ffea1e0  A4      : 0x00000006  A5      : 0x00000001
A6      : 0x0000002a  A7      : 0x3ffea310  A8      : 0x00000000  A9      : 0x3ffea1b0
A10     : 0x00000002  A11     : 0x3ffea1b0  A12     : 0xffffffff  A13     : 0x00000000
A14     : 0x0000000a  A15     : 0x3ffea2f0  SAR     : 0x0000000c  EXCCAUSE: 0x0000001c
EXCVADDR: 0x00000000  LBEG    : 0x40092652  LEND    : 0x4009265d  LCOUNT  : 0x00000000
ELF file SHA256: 0000000000000000
Backtrace: 0x401c5019:0x3ffea1b0 0x401b6778:0x3ffea1e0 0x401c55c5:0x3ffea210 0x401c5756:0x3ffea230 0x401b58f1:0x3ffea270 0x401315b1:0x3ffea290 0x4012f634:0x3ffea2f0 0x4014c621:0x3ffea310 0x4014c8d1:0x3ffea330 0x40121380:0x3ffea390 0x40125e71:0x3ffea3b0 0x40126035:0x3ffea460 0x40133f74:0x3ffea480
Rebooting...
ets Jun  8 2016 00:22:57
rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0018,len:4
load:0x3fff001c,len:2984
load:0x40078000,len:10700
load:0x40080400,len:5236
entry 0x40080658
E (562) psram: PSRAM ID read error: 0xffffffff
E (562) spiram: SPI RAM enabled but initialization failed. Bailing out.
E (562) spiram: SPI RAM not initialized

I know that re-flashing helps to "fix" the board but I need t0 find a way to turn wifi off.
I will be much thanksful for your advice.