I'm not sure if HKJ reviewed the 2-button version Miboxer C4-12.. He did review the original 1-button Miboxer C4-12 that had a USB-out function.
The 2-button version Miboxer C4-12 actually has some revision in the later batch too.
Some noted difference of the earlier Miboxer C4-12 (2-button) v2 with a recent Miboxer C4-12 (2-button) v2.2 ("v2.2" is indicated in the manual only, not on the charger):
(the v2 and v2.2, both 2-button versions of C4-12s look physically the same)
I) Miboxer C4-12 v2 (2-button):
a) has A for automatic charge current selection, when cycling the charge current (ie. user-selectable charge current can cycle from 0.1A up to 3.0A, then the "A" (automatic setting) then back to 0.1A
b) automatic charge current selection appears to be solely based on the measured IR by the charger, so if it's a small capacity battery that has a very low IR, then it will automatically charge at higher charge current (as high as 3A if the measured IR is low enough) (user can manually select charge current, or go back to the "A" automatic setting)
c) the charger will display IR measurement even when the battery is at 4.20v
II) Miboxer C4-12 v2.2 (2-button):
a) when battery is first inserted, it uses Automatic charge current selection (appears to be based on the measured IR), but when user-selecting the charge current, it cycles from 0.1A to 3A, but not the "A" (automatic) setting
b) the automatic charge current appears to still be based on the measured IR, but now there is an upper limit of 2A (i;e. when the IR is very low, it will charge at max 2A automatically; user can still manually select own charge current)
c) the charger does not display IR value anymore when the just-inserted battery is nearly full voltage (ie. if the battery just inserted into the charger is at 4.16v or higher, then the IR display will just indicate "---", in contrast with v2, it will still show an IR value)