The bmp.blob in /bootloader is what gets written to the BMP partition. That hasn’t changed. It’s the bmp.blob itself that’s different - we had to go to a compressed format for Jetson Nano, due to the constraints of the QSPI chip used on that platform (4MB). So every Jetson build got that new compressed format for the bmp.blob.
It’s the same 3 BMPs (NVIDIA green-on-black logo, in 480, 720 and 1080), with the same header that describes those files. The header is generated by the blob creation script. I’m trying to get that released publicly.
For the compressed blob, the header is essentially the same, and it’s followed by the 3 BMP files compressed by lz4c.