How to increase index row maximum size in Postgresql?

I want to perform KNN on 512-dimensional vector using the solution suggested here . 1. I couldn't create table with 512-d cube array. Solved by changing the CUBE_MAX_DIM in the source code. 2. Couldn't create index on table with dimensions > 200. Set block_size=32. Now works with dimensionality<=510. 3. Got new error after changing block_size and trying to create index on table with 512-d vectors ERROR: index row requires 8208 bytes, maximum size is 8191 Is it possible to increase this limit?