+QFUPL: How is the checksum calculated?

Docs say that the response to AT+QFUPL is:
+QFUPL: <upload_size>,<checksum>

I’m uploading successfully, but can’t figure out how the module is calculating the checksum.
For example, if I upload my 1187 byte cert, the module reports:
+QFUPL: 1187,2d19
but I can’t figure out how it’s calculating 2d19.

I read this post:
but neither algorithm produces the 2d19 checksum that’s reported with the +QFUPL:

Could you provide some insight? Maybe the crc-calc code snippet from the module itself?


@dlchambers_aperia Did you ever figure this out?

@knodi Nope :frowning:
You’d think Quectel could just post the source to their function. CRC-calc is pretty simple…