My original adapter stopped working which was of 12V - 1Amp = 12W. Can I use 12V - 0.5Amp = 6W adapter to power my router? Will it work as expected or not? Also this router is dual band !

I am unable to register my Archer A6 router on My Product Register webpage within India. The country is auto selected to US and can't be changed. Kindly help me in registering my product within India.