Differences

This shows you the differences between two versions of the page.

--- semi-invasive [2018/02/25 09:15] – mcmaster
+++ semi-invasive [2019/12/08 19:23] (current) – mcmaster
@@ Line 1: / Line 1: @@
-====== Photonic (UV) EPROM erase ======
+====== UV EPROM erase ======
 EPROM/EEPROM/flash can be erased by shining UV light or x-rays into the surrounding oxide. This slightly oxidizes it, letting the floating gate to drain out.
+Usually a masking compound is applied to selectively block UV to the firmware, with red nail polish being the most popular or at least traditional.
+{{:mcmaster:nail_polish:overview.jpg?400|}}
+McMaster misc notes
+Application
+  * Use a single hair brush
+    * Ex: cut down MG 855-5 horse hair brush
+  * Place chip in bowl
+  * Shallow fill bowl with acetone
+    * Creates shield gas to prevent nail polish drying out in small quantities
+    * Place paper towel on side to elevate gas enough to keep nail polish liquid
+  * If nail polish is too viscous, slightly set top of chip with IPA
+  * Apply a glob of nail polish, then use the spring force of the liquid to precisely move it around
+    * By gently agitating the liquid boundaries its possible to very precisely move it forward
+  * Place the nail polish in the bowl in some sort of holder
+    * Ex: above image has a 1/4-20 SHCS with a nut screwed on as a base
+Nail polish
+  * [[https://www.amazon.com/gp/product/B00LT8S30G/|Revlon ColorStay Gel Envy Longwear Nail Enamel, Queen of Hearts]]
+  * Also can be used to look fabulous!
+  * Bought at local store a while back and it seems to work well enough
+  * Other colors probably fine, but red is easy to see
+{{:mcmaster:nail_polish:pipette.jpg?400|}}
+Above: fine polypropylene tip for more aggressive cleaning. The tool is strong enough to damage bond wires though, so use sparingly
+Nail polish removal
+  * Bulk removal with acetone, but leaves some residue around edges
+  * Remaining residue softened with acetone
+  * Remove using single hair brush if possible
+  * Can be more aggressive with PP monofilament wire
+  * Cold H2SO4 also works well. Wash with IPA then acetone
+    * Washing with water may really heat up the mixture
 ===== Angle =====
@@ Line 16: / Line 54: @@
-====== Non-invasive attacks ======
+====== X-ray EPROM erase ======
-[[jtag|JTAG]]
-[[ripping|Ripping firmware]]
-[[dpa|Differential power analysis]]
+TODO: add links to misc papers