“cros_workon info --board=samus --all | grep kernel” [1] seems to indicate that *all kernel versions* are being mapped to v4.4, which is wrong. 
Copying briannorris@' explanation here: “From a quick read of the chromite sources for the 'info' command, they seem to erroneously assume that a given repository (e.g., kernel.git) is only checked out in a single location. So all kernel ebuilds get mapped to .../kernel/v4.4.”

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(cr) ((4a5af05...)) kirtika@kirtika ~/trunk/src/scripts $ cros_workon info --board=samus --all | grep kernel
dev-util/turbostat chromiumos/third_party/kernel src/third_party/kernel/v4.4
sys-kernel/chromeos-kernel-3_10 chromiumos/third_party/kernel src/third_party/kernel/v4.4
sys-kernel/chromeos-kernel-3_14 chromiumos/third_party/kernel src/third_party/kernel/v4.4
sys-kernel/chromeos-kernel-3_18 chromiumos/third_party/kernel src/third_party/kernel/v4.4
sys-kernel/chromeos-kernel-3_8 chromiumos/third_party/kernel src/third_party/kernel/v4.4
sys-kernel/chromeos-kernel-4_4 chromiumos/third_party/kernel src/third_party/kernel/v4.4
sys-kernel/linux-firmware chromiumos/third_party/linux-firmware src/third_party/linux-firmware
(cr) ((4a5af05...)) kirtika@kirtika ~/trunk/src/scripts $