Sentinel-1 border noise removal procedure for products from IPF 2.34 < version < 2.5

Dear all,

Here is my problem: I have some rather old S-1 GRD IW products (from october to december 2014) for which I want to remove the border noise. In SNAP, neither the S-1 Thermal Noise Removal nor the S-1 Border Noise Removal allowed to completely remove such noise. I am aware of this document Masking “No-value” Pixels on GRD Products generated by the Sentinel-1 ESA IPF but it seems that the procedure described is missing something, for old products with IPF version << 2.5.
I am wondering if there is a particular procedure or if the scaling factor for the noise is different for IPF versions lower than 2.4 or maybe older (?). I couldn’t find a document on this matter online yet.

Thank you very much and best regards,

Antoine Ba