However the related documentation states that it supports blocksize in either 512, 1024 or 2048 in bytes. Please confirm if the above statement is correct. My experiments showed that blocksize other than 512byes fails the boot with 'unsupported blocksize' message.
I've checked with our developer team and what you have found is correct, only the 512 byte blocksize is supported. I have submitted a request to update our User Guide. Was that where you found this incorrect information?