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Deze versie is geschreven door: Andre De Guerin ,

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Don’t ask how I found this out, but the chip in “official” TouchID buttons isn’t actually OTP after all.
-Its actually an e2prom but with the external write voltage line routed through a fuse so when written it gets “Zapped” and goes open circuit.
+Its actually an e2prom but with the external write voltage line routed through a cell fuse so when written it gets “Zapped” and goes open circuit or at least very high resistance in order that any attempt to rewrite it would then fail.
The way to fix this would be wiping the chip with X-rays. Needless to say it would be dangerous but UV light may work as it has done with many smaller chips of which this is likely to be. Cell size is probably in the micrometre range so should be feasible with something like a Cool-X or similar.

Status:

open

Origineel bericht door: Andre De Guerin ,

Tekst:

Don’t ask how I found this out, but the chip in “official” TouchID buttons isn’t actually OTP after all.

Its actually an e2prom but with the external write voltage line routed through a fuse so when written it gets “Zapped” and goes open circuit.

The way to fix this would be wiping the chip with X-rays. Needless to say it would be dangerous but UV light may work as it has done with many smaller chips of which this is likely to be. Cell size is probably in the micrometre range so should be feasible with something like a Cool-X or similar.

Status:

open