Same issue happening with me when im trying flash my eMMC, i flashed the new update recently without anyprobs from the same machine.

flasher v3.5

Image 'mmc', size 241163 kB
Version RX-51_2009SE_1.2009.41-1.VANILLA
Suitable USB device not found, waiting.
USB device found found at bus ***, device address ****
Found device RX-51, hardware revision 2101
NOLO version 1.4.14
Version of 'sw-release': RX-51_2009SE_2.2009.51-1_PR_MR0
Booting device into flash mode.
Suitable USB device not found, waiting.

followed by dead progression dots . nothing happening after that. (waited for few min) even after i unplug the usb cable and the dots stays there and i need to take the battery out to turn it off..ohh my bat is at 60% , does it need to be exatcly 100% to flash emmc ?