Infinite boot loop

Hi, all!
I`m having trouble with firmware newer than 1.87, no matter which boot version is uploaded (tried 1.6, 1.5, 1.4) the module goes to infinite boot loop

 ets Jan  8 2013,rst cause:2, boot mode:(3,0)

load 0x40100000, len 2408, room 16 
tail 8
chksum 0xe5
load 0x3ffe8000, len 776, room 0 
tail 8
chksum 0x84
load 0x3ffe8310, len 632, room 0 
tail 8
chksum 0xd8
csum 0xd8

2nd boot version : 1.6
  SPI Speed      : 40MHz
  SPI Mode       : QIO
  SPI Flash Size & Map: 8Mbit(512KB+512KB)
no GPIO select!
jump to run user1 @ 1000

rf_cal[0] !=0x05,is 0xFF

load 0x40100000, len 1856, room 16 
tail 0
chksum 0x63
load 0x3ffe8000, len 776, room 8 
tail 0
chksum 0x02
load 0x3ffe8310, len 552, room 8 
tail 0
chksum 0x79
csum 0x79

2nd boot version : 1.5
  SPI Speed      : 40MHz
  SPI Mode       : QIO
  SPI Flash Size & Map: 8Mbit(512KB+512KB)
jump to run user1 @ 1000

rf_cal[0] !=0x05,is 0xFF

On 1.87 the module boots pretty fine even with 1.6 boot version

The module is ESP-01 with 1Mb of flash

Here is the esptool upload terminal string

D:\esp8266\esptool>esptool.py -p COM2 -b 115200 write_flash --flash_freq 40m --f
lash_mode qio --flash_size 1MB 0x0000 D:\esp8266\espruino\188\boot_v1.5.bin 0x10
00 D:\esp8266\espruino\188\espruino_esp8266_user1.bin 0xFE000 D:\esp8266\espruin
o\188\blank.bin

Any ideas? Thanks in advance!