Firstly why are you flashing firmware? (if its a damaged controller, failing to connect, it also won't come back from a firmware flash). Controllers are preflash from the factory
turned cnc on last night and I don't know what happend but when i tried to home the movement speed was slow and reverse and then i lost the home icon. turned off the back on I noticed that unlock icon was not flashing I pushed the reset button on black box nothing helped
That's incorrect Grbl Settings. You somehow changed/wiped your Grbl Settings. Load your backup you took when it was all working well from Grbl Settings > Restore backup > Select the backup file you saved somewhere safe when everyting was till fine If you forget to backup, then you are in for setting it up from scratch like you did the first time (and then remember to backup for next time) Firmware update not the solution
CONTROL > Grbl Settings tab. If its one of our machines, select machine from list > save and reset when prompted If its a custom machine, you've gone through setting it up once before, mainly figuring out your parameters. Use nearest similar machine (or the CUSTOM profile) and modify accordingly Grbl v1.1 Configuration (also on the Grbl Settings tab)
Use the lead 1515 profile and shorten the 1000mm axis you have by 500mm (x or y whichever is shorter)