The fcam drivers can be manually uninstalled if still present AFTER removing BlessN900 and fcamera.

KP52 can be uninstalled only by using the proper uninstaller and not simply removed via HAM. Doing the latter will cause problems. Camera-ui2 comes with CSSU.

CSSU cannot be uninstalled. A reflash is the best option - cold comfort in the case of a flaky usb port I know.