The backup battery is gone because Intel datasheets advised against it for years, and they got more insistent over time. It's surprising enough that they still

The backup battery is gone because Intel datasheets advised against it for years, and they got more insistent over time. It's surprising enough that they still didn't manage to kill of that part of the PC80 architecture (RTC clock and associated memory). They certainly try for years by now. As for the TPM, Chromebooks come with them for a long time now. They're cleared when entering or leaving developer mode. The main difference is that after clearing, the devmode mechanism also records the state there (instead of in CMOS). If you're concerned about "final keys", read the spec (eg. http://www.trustedcomputinggroup.org/resources/tpm_main_specification http://www.trustedcomputinggroup.org/resources/tpm_main_spec..., Part 1, Section 9.5). The only key that is never deleted is the "Endorsement Key". That one is similarly annoying as the Pentium III serial number (ie. it allows secure identification of the TPM if you let software send requests to the TPM).