Bought 1 for modding, since H04 double priced and D10 quality degradeted with years. H1 host similar to Skilhunts H04, good heat dissipation, easy to repair or mod,… but heavier, “thanks” to battery fat tube witch weights 37gr. alone. Driver linear, constant current - It is fine, but UI … 
Horrible linear dimming and stepped mode spacing, too slow mode switching, turbo with memory in main line, no reverse option, not accessible moon level from main line and it is almost same brightness as low mode, conservative LVP behavior - steps down from any level to low (5mA) at 3V and goes off at 2,8V. Also found few non critical bugs related to issues mentioned above. When Voltage < 3V, “moon” mode after few sec. switches to low mode. Another bug : Off > turbo > off > turbo > double click… and nothing happens, because stays at the same memorized turbo ;))
Button PCB have 2 leds. 1 red , 1 green. Red is connected, green not at all.
So, before replacing stock driver with my buck driver i had to remove green and add another red in parallel.
