Before taking any step in order to rewrite the firmware you have to determine the manufacturer of the system on chip. On tablets we have two main manufacturers that we use, Mediatek and Allwinner.
Allwinner based devices:
Magnet W10
Navo P
Navo S
Mediatek based devices:
Argus QS
Druid L10
Emerald 78E
Epic E7
Epic E8
Epic M8
Epic P7
Magnet M1
Magnet M9
Navo QS
Onyx Q
Onyx QS
Onyx XS
Onyx Z
Orin QS
Orin S
Otis QS
Otis S
Pluri B7
Pluri C7
Pluri C8
Pluri M7
Pluri Q8
Sirius Evo Z
Sirius QS
Sirius QSX
Spirit QS
Spirit S
Vario QSX
Xara QS
Xavy L8
Xavy G7
Xavy T7