There is no effect of a year back in BTECH during  MTECH placements.  The recruiters will only see your resume , your average marks in Mtech and will only look at your knowledge and skills and nothing else. The past is past , they see the present and how can you do well for them when they give you a job
. So don't be in a dilemma that it will have any impact on your Mtech  placements . If you have done any major and minor projects then it is well an good for you and for the company who will hire you .So all the best don't worry about it .