unable to flash esp8285 firmware

I want to flash/erase because of buad rate is unknown
I try many baud rate, but no success

It used to work normally, but some days later, not work any more.

when esp8285 is booting, buad rate is 115200 just fine
but when it continue to load at 0x1000, buad rate was change to unknown
So I cannot use WiFi because of buad rate

 ets Jan  8 2013,rst cause:1, boot mode:(3,6)

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       : DOUT
  SPI Flash Size & Map: 8Mbit(512KB+512KB)
jump to run user1 @ 1000

rf[112] ⸮)͈⸮

I think I should erase flash/param in ESP8285
but when I try to flash, no response from esptool
unable to start flash

when esp8285 enter flash mode, ready to flash

 ets Jan  8 2013,rst cause:1, boot mode:(1,6)

esptool can’t sync

esptool.py v2.8
Serial port COM6

My fualt, TX line was disconnected.