After direct X,Stayman and major suit transfer are on. Redouble asks opener to bid 2§.

Same applies after 1NT overcall of a minor, but

(1♥) 1NT (X) XX = minor one suiter

2C = C + S

2D = D + S

2H = xfer

(1♠) 1NT (X) XX = minor one suiter

2C = C + H

2D = D + H

2H = natural

1NT (P) P (X)

P (P) XX = minor one suiter

2C = C + another

2D = D + another

2H = H + S