I tried to update the firmware, and now i cant seem to get out of the error 528. Ive tried to downlead out of the box .hex, and microbit V2.21 newest firmware .hex, but no luck ):
i tried flashing microbit firmware again for v2.21 from microbit.org to my microbit while in maintenance mode, but i got a fail.txt file and still have error: 5, 2, 8, sad face.
This support page from the micro:bit website lists a lot of the error codes and their meaning: https://support.microbit.org/support/solutions/articles/19000016969-micro-bit-error-codes
For error code 528:
The micro:bit has detected an unsupported update. This can occur if you attempt to flash a firmware .hex file whilst in normal MICROBIT mode. Try flashing a file created in one of the online editors to resolve the issue.
More info about the firmware.hex file can be found in the https://microbit.org/get-started/user-guide/firmware/ page. It's esentially a hex file used to update the "interface chip" (the microcontroller that handles all the USB features). That hex file is only meant to be flashed to the MAINTENANCE drive, which appears in "maintenance mode", and not into the "normal" MICROBIT drive where the user programme hex files are flashed.
If you flash any hex file created with the MakeCode or Python Editor into the MICROBIT drive it should clear the error code and run your programme.