ARM big.LITTLE systems started out as use one or the other, but not both simultaneously. Advertising those as 8 core when it's really big 4 or LITTLE 4, or later incantations where you could use the big or LITTLE of each of the four paired processors, is sketchy, but was common.
If the plan was to allow big 4 or LITTLE 4, and then a hardware bug became apparent that you could switch to LITTLE cores but not back to big cores, well you notify customers and stop advertising the LITTLE cores. archive.org has them mentioned Jun 1 2016 [1], and then removed Jun 14, 2016 [2]; the A53 cores aren't mentioned but are shown in the die map on the current page [3].
If the plan was to allow big 4 or LITTLE 4, and then a hardware bug became apparent that you could switch to LITTLE cores but not back to big cores, well you notify customers and stop advertising the LITTLE cores. archive.org has them mentioned Jun 1 2016 [1], and then removed Jun 14, 2016 [2]; the A53 cores aren't mentioned but are shown in the die map on the current page [3].
[1] https://web.archive.org/web/20160601063237/http://www.nvidia...
[2] https://web.archive.org/web/20160614200203/http://www.nvidia...
[3] https://developer.nvidia.com/content/tegra-x1