solved...sort of ... looks to be win7 problem - works fine on up to date win 10

from arduino serial monitor @ 115200 baud :

==========================
rst:0x1 (POWERON_RESET),boot:0x17 (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:1
load:0x3fff0018,len:4
load:0x3fff001c,len:1216
ho 0 tail 12 room 4
load:0x40078000,len:9720
ho 0 tail 12 room 4
load:0x40080400,len:6352
entry 0x400806b8
M5Stack initializing...OK

so the serial port seems to be working OK - but loader never connects

gray m5 core

Win7 - loaded tetris from arduino UI successfully. no trying to re-flash anything from arduino or m5burner it looks like the tetris load does not let the bootloader start. on any load attempt the system resets and then the tetris start screen appears. this repeats till the loader times out trying to connect. forcing a reset via the power button has no difference than the usb induced reset