The iBooster assertion has failed according the ANSI C standard. 

When an assertion fails the following occurs:

• The failure is stored in the electrically erasable programmable ROM (EEPROM) (failure memory).
• The program flow is aborted, and the electronic control unit (ECU) is shutdown electrically (only in the power cycle when the assertion failed).

In the next power cycle, the already failed assertion is detected, and the system is shutdown hydraulically to  read the failure memory. Assertions are only active if NDEBUG is not set by the compiler (see also ANSI C standard).