@charly86 and while there at it they can also mention that p8 must not be pulled up when you want to flash the firmware. because if you don't it wont get into download_boot mode but instead into HSPI_FLASH_BOOT mode and will start a reset loop. we also had that problem.

@Ricardo-M I boot my sipy in safe mode and i connect pc and sipy by telnet (using Putty) and i carry out a factory reset to the filesystem (reset flash filesystem) and now my sipy is like new