Possible issues with large(ish) files [Resolved]

Interesting update. This time when I called eraseAll I got this instead. I think I've corrupted the system overall, better start from scratch, brb.

UPDATE: Please ignore this, possibly a red-herring from an unclean file-system.

[255] ?[255] ?[255] ?[255] ?[255] ?[255]...
                                                                                                                                                                                                                                                                                                                                                                       ^
in function called from system
Uncaught SyntaxError: Got ?[255] expected EOF
 at line 1 col 1
?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255]...
                                                                                                                                                                                                                                                                                                                                                                       ^
in function called from system
Uncaught SyntaxError: Got ?[255] expected EOF
 at line 1 col 1
?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255]...
                                                                                                                                                                                                                                                                                                                                                                       ^
in function called from system
Uncaught SyntaxError: Got ?[255] expected EOF
 at line 1 col 1
?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255]
                                                                                                                                                                             ^
in function called from system
 at line 1 col 1