Yes you can participate in the second round of TS EAMCET counselling but if you get a seat in the second counselling then you will loose your seat that you got in the first counselling. Even if you get a less good college than the one you got now you will have to take the seat that you got in the second counselling you will not be eligible to take the seat in the college that you got in the first counselling but if you do not get any college in the second counselling then you can take the seat that you got in the first counselling.

you can select colleges which are better than the college and group you have been alloted in 1st counselling and if you don't get seat in second counselling then you get the seat which you have been alloted in first counselling [ONLY IF YOU PAID FOR THE SEAT YOU HAVE BEEN ALLOTED IN 1ST COUNSELLING AND ACCEPTED THE JOINING REPORT IF NOT YOU WILL GET NO SEAT].