should i have 2 qualify in both jee mains paper 1 and paper 2 , to apply for jee advance in paper 2 i.e b.arch?

hii

well not required buddy you should just qualify only any one and few criteria mentioned below

All the candidates must fulfil each and every one of the following five criteria to appear in JEE (Advanced) 2018.
Criterion 1 – Performance in JEE (Main) 2018 : Candidates should be among the top 2,24,000* (including all categories) in Paper-1 of JEE (Main) 2018.

The percentages of various categories of candidates to be shortlisted are: 27% for OBC-NCL, 15% for SC, 7.5% for ST and the remaining 50.5% is OPEN for all. Within each of these four categories, 5% horizontal reservation is available for PwD candidates.

The following table show the order to be followed while choosing top 2,24,000* candidates in various categories based on the performance in Paper-1 of JEE (Main) 2018.

Category-wise distribution of top 2,24,000* candidates (Criterion 1)

* The total number of candidates can be slightly greater than 2,24,000 in the presence of “tied” ranks/scores in any category.

Criterion 2 – Age limit : Candidates should have been born on or after October 1, 1993. Five years relaxation is given to SC, ST and PwD candidates, i.e., these candidates should have been born on or after October 1, 1988.

Criterion 3 – Number of attempts : A candidate can attempt JEE (Advanced) a maximum of two times in consecutive years.

Criterion 4 – Appearance in Class XII (or equivalent) examination : A candidate should have appeared for the Class XII (or equivalent) examination for the first time in either  2017 or 2018.

However, if the examination Board of Class XII (or equivalent) declares the results for the academic year  2015-16 after June  2016, then the candidates of that board who appeared for their class XII exam in 2016 are also eligible to appear in JEE (Advanced) 2018, provided they meet the other eligibility criteria.  In case, the examination Board of Class XII (or equivalent) declared the results for the academic year 2015-16 before June 2016 but the result of a particular candidate was withheld, then the candidate will not be eligible to appear in JEE (Advanced) 2018.

Criterion 5 – Earlier admission at IITs : A candidate should NOT have been admitted in an IIT irrespective of whether or not he/she continued in the program OR accepted an IIT seat by reporting at a reporting centre in the past. Candidates whose admission at IITs was cancelled after joining any IIT are also NOT eligible to appear in JEE (Advanced) 2018.

Candidates who have been admitted to a preparatory course in any of the IITs for the first time in 2017 can appear in JEE (Advanced) 2018.

The candidates who paid seat acceptance fee in 2017 but (i) did not report at any reporting centre OR, (ii) withdrew before the last round of seat allotment, OR, (iii) had their seat cancelled (for whatever reason) before the last round of seat allotment for IITs, during the joint seat allocation in 2017 are eligible to appear in JEE (Advanced) 2018.

However, in any of the above cases, the candidate is required to fulfil the conditions mentioned from criterion 1 to criterion 4.

all the best