After setting database read_only if i take transaction log backup with no truncate , does it have side affect?

I want to take transaction backup of database, but i want the log have the last transaction in it.

With no truncate option supports this. But via sql manegment studio, it leaves the database recovery state.

when you leave the database recovery state, you have to restore the last transaction to get normal. And after restoring the transaction log you destroy the backup sequence.

Instead i found a new method, i want to ask if it has a side affect;

Scenerio;

1)  set database read_only

2) take transaction backup with no truncatewith t-sql (By this way you do not have to specify to leave the database  recovery mode)

3) And other transaction log backups (with truncate_only) can go on..... And you are sure that,the last transaction is in the first transaction log backup that we took via no truncate option

Is there a problem with this scenerio?