Nordic Build code for XIAO BLE?

If one were to use the XIAO in a commercial product, you’d want to protect the flash from reading to protect your software. But some nRF52840’s are subject to glitching attacks that can read the flash.

Supposedly “build code Fxx” and later have this addressed.

Normally you can just read this build code off the chip, but where the XIAO’s nRF52840 is covered by a can, this isn’t possible? How can one determine if the device is subject to the glitching bug? Are nRF52840 XIAO’s new enough that this isn’t a worry?


To answer my own question, NRF_FICR->INFO.VARIANT does seem to indicate the variant and build code.

On my XIAO BLE’s, the value is 41414430, or AAD0, which according to this means “Dx0” build code.
{“AADx”, REV_2, “QIAA”, “Dx0 aQFN73 1MB 256kB”, mNRF52840_Anomalies}, //
{“AADx”, REV_2, “CKAA”, “Dx0 WLCSP 1MB 256kB”, mNRF52840_Anomalies} //

So Dx0 build code is earlier than Fxx as per the errata, so I guess this generation of XIAO’s doesn’t allow proper code protection. :frowning: