If the micro:bit runs out of resources or detects a fault, it enters a 'panic' routine which displays a sad face on the micro:bit screen followed by a number eg 529.



In all cases, pressing the reset button on the back of the micro:bit will restart the program, which clears out the RAM memory and starts again.


Here is a list of errors with descriptions of what they mean and what you can do to fix. We also document them all here individually on the support site:


Hardware errors (010-099)

                                                                                                                                       
Error number        What this means        
010        The micro:bit's I2C bus is not working. The device might be physically damaged.        
020        There is no free memory on the micro:bit. Your program might be too complex or contain a lot of large variables.          Try reducing your code by making functions out of large sections.        
030        Corruption detected in the micro:bit heap space (memory allocated usually for the storage of variables).          Try flashing a different .hex file to your device        
040        Your micro:bit can't execute your script properly. Flash a different .hex file to it, then try flashing and running your previous script again.        
042        Your micro:bit can't execute your script properly. Flash a different .hex file to it, then try flashing and running your previous script again.        
043        An error occurred with the micro:bit's radio component.        
050        An error occurred with the micro:bit's accelerometer component.        
051        An error occurred with the micro:bit's magnetometer component.        
098        Assertion failed. A MakeCode error that occurs when the condition in an assert was false.


MakeCode Editor errors (800 - 989)

 

Error codes generated from the MakeCode Editor. In all these cases, please report the error to us, or if you are comfortable using Github, submit an issue on the code repository.

Garbage collector errors

Error number        What this means
840Allocation pointer is null or invalid.
841Garbage collection work queue error.
843VTable entry is not free.
844GC allocation failed for requested number of bytes.
846Invalid allocation thread.
848Allocation pointer beyond allocation header.
849Allocation pointer is null.
 

Program access errors

                                                                                                                         
Error number        What this means
901The type header for the object is not valid.
902The object data portion is greater than the length defined for it.
903An object reference was deleted and the object is no longer valid.
904The object size doesn’t match the size defined for the type.
905An object vtable is invalid or not initialized.
906An internal resource error.
907The specified device resource is not present.
909The argument value is out of range or the type or format is invalid.
927
The program is incompatible with the micro:bit version you are using. You are trying to use a feature designed for micro:bit V2 on a micro:bit V1 or an extension that is only compatible with a micro:bit V1 board on a micro:bit V2.
 

JavaScript runtime codes

 

These occur for example, when the static type of x is a class c, the dynamic type of x isn’t c, and you try to access a field on x or call a method on x, you will get one of the following codes, depending on dynamic type of x.

                                                                                                           
Error number        What this means
980When value of x is undefined.
981When value of x is true or false.
982When x is a number.
983When x is a string.
984When x is object of some type.
985When x is a function.
989When x is a null.



If you are using one of the standard languages such as MakeCode or MicroPython, you would not often see these error messages. If you do, please report them to us so we can investigate. 


If you are using C++, then these errors are more likely if you have a bug in your C++ program.


USB DAPLink errors (500 - 599)

Errors that begin with a indicate an error when flashing a file to the micro:bit via USB. Common errors are explained below, but please report them to us including your DETAILS.TXT file from the  MICROBIT drive if you see errors in the range 500-599 occurring often.


Error number
What this means
502
The micro:bit has experienced an internal error. This can occur during the drag and drop flash process. Try disconnecting and reconnecting the micro:bit to resolve the issue.
504The transfer of the hex file to the micro:bit has timed out. This means that that flashing process has taken too long. We are currently investigating this error, so if it occurs more than once please report it to us including your DETAILS.TXT file from the MICROBIT drive and the .hex file that caused the issue. This error might also occur if the file does not have the .hex extension
506
The hex file is out of order. This means the code in the .hex file is in an order that the micro:bit did not expect. This might occur if you drag and drop a .hex file to the device before the previous one has finished flashing.
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.
529
The micro:bit has detected an incompatible image. This can occur when you If you attempt to use an old .hex file with the latest micro:bit. Try updating the hex file in the editor in which it was created and downloading it again.

 


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