There is a large gap between previously discussed non-invasive ic program attack and invasive microcontroller unlocking, many mcu crackers fall into this gap, being not so expensive as classical penetrative invasive ic attacks but as easily repeatable as non-invasive program attacks.

Therefore we decided to define and introduce a new class of program attack called semi-invasive. Like invasive chip program attacks, they require depackaging the chip in order to get access to its surface. However, the passivation layer of the chip remains intact, as semi-invasive methods do not require depassivation or creating contacts to the internal lines. This is because microprobing is not used for this mcu program attack technology and thus such expensive tools as laser cutters and FIBs are not required.