LineageOS (ex-CyanogenMod)'s flavour of Android 7 works just fine [1] on Nexus 5. On the other hand - yes, hammerhead is stuck on Linux kernel 3.4, which is no

LineageOS (ex-CyanogenMod)'s flavour of Android 7 works just fine [1] on Nexus 5. On the other hand - yes, hammerhead is stuck on Linux kernel 3.4, which is no longer maintained, and current best effort to forward-port to mainline kernel [2] is far from complete. Among other things this means that there is no workaround for Meltdown on this hardware, which it is likely vulnerable to. [3] [1] https://download.lineageos.org/hammerhead https://download.lineageos.org/hammerhead [2] https://wiki.postmarketos.org/wiki/Google_Nexus_5_(lg-hammerhead)#Component_support_table https://wiki.postmarketos.org/wiki/Google_Nexus_5_(lg-hammer... [3] "11 stage integer pipeline with 3-way decode and 4-way out-of-order speculative issue superscalar execution" - from https://en.wikipedia.org/wiki/Krait_(CPU) https://en.wikipedia.org/wiki/Krait_(CPU)