I just tested the new V-52 firmware and discovered, that firmware updates fails if the sd card is formatted in the new exfat format. The K2.bin on the sd card is simply deleted, but no update occurs. This could bring new customers/users into trouble, as the V-52 firmware now always formats the sd card as exfat when using the app.
Means: If someone installs the new V-52 firmware and formats his sd card using the app, he will not be able to do any further firmware updates, as long as he does not re-format the sd card as fat32 (or use a different sd card).
Flashing-Log looks like this
NP>TLoader Start ...663_DDR3_LV1_587_2048Mb 05/10/2018 11:33:42Rcard open fail
It seems that the bootloader, which is responsible for flashing, cannot handle the exfat format ("card open fail") and therefore fails. After that, the normal boot process deletes the K2.bin.
Normal flashing-log looks like this
NP>TLoader Start ...663_DDR3_LV1_587_2048Mb 05/10/2018 11:33:42RRRRWDT initRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRFullCompSPI NOR detectedUd FWeeeeeeeeEEEEEEEEEEEE...and so on.
I'm not sure if your developers can fix this, because as far as I know (and understand the K2), the bootloader cannot be flashed using the normal update process. It can only be flashed using the usb port and a special program.