SUPER privilege not defined for master user in Amazon MySQL RDS
You can try to change log_bin_trust_function_creators; however, there is an alternative approach that seems more appropriate when you consider the meaning of that variable:

It controls whether stored function creators can be trusted not to create stored functions that will cause unsafe events to be written to the binary log.
A setting of 0 also enforces the restriction that a function must be declared with the DETERMINISTIC characteristic, or with the READS SQL DATA or NO SQL characteristic. If the variable is set to 1, MySQL does not enforce these restrictions on stored function creation.

All that option does is assume that you know what you are doing, without making you assert that you do by using one of the three characteristics in your CREATE statement... but if you don't properly declare the function, you may miss out on potential optimizations.

misdeclaring a routine might affect results or affect performance

Taken together, this implies that the most correct approach is to declare your stored functions with DETERMINISTIC or READS SQL DATA or NO SQL as appropriate, and, if these do not correctly describe your function's behavior, then your function still may result in unsafe statements being written to the binary log, because these options are also &quot;trusted:&quot;

Assessment of the nature of a routine is based on the “honesty” of the creator: MySQL does not check that a routine declared DETERMINISTIC is free of statements that produce nondeterministic results.


Curious aside: astute observers will note that I omitted something from the documentation's description:

If set to 0 (the default), users are not permitted to create or alter stored functions unless they have the SUPER privilege in addition to the CREATE ROUTINE or ALTER ROUTINE privilege.

Since nobody gets SUPER in RDS, and assuming this is not an error in the official documentation, this seems like it must be an AWS customization of MySQL behavior.