And yes Im using a Prolific TTL cable, I modified esptools.py to handle the issue which is a back to back writes can cause buffer overruns in the prolific driver. works fines upto 115200 now!!!!.
I can patch in esptools.py anyway into the platform.txt if thats the issue with esptool.ck ( Yet I see there are comments that the flash part of that is buggy too !).
Revert soon.