Magnetoresistance of the 2D organic superconductor (BEDO-TTF)(2)ReO4.H2O, w
hich is known to undergo phase transitions vs pressure, temperature and mag
netic field, has been measured with different field orientations up to 52T
at ambient pressure. The modification of the quantum oscillations spectrum
as the magnetic field increases, is studied in connection with the sample q
uality.