Correct format for RCLONE_B2_DOWNLOAD_URL variable?

I'm having challenges getting the URL format right for RCLONE_B2_DOWNLOAD_URL.

I have setup a Cloudflare-proxied CNAME to the Backblaze CDN url (httpx://f001.backblazeb2.com/file/) that works with httpx://f001.backblazeb2.com/file/bucket. I can confirm that I am able to access files from the public bucket through the CNAME of dl.example.com through the Cloudflare Proxy.

I continue to face the same error.

When using rclone copy:

notroot@example:/opt/b2# rclone copy b2:/example_bucket/test.jpg /var/www/test.jpg
2020/04/10 01:07:47 ERROR : test.jpg: Failed to copy: failed to open source object: failed to open for download: bucket example_bucket does not have file: /b2api/v1/b2_download_file_by_id (404 not_found)
2020/04/10 01:07:47 ERROR : Attempt 1/3 failed with 1 errors and: failed to open source object: failed to open for download: bucket example_bucket does not have file: /b2api/v1/b2_download_file_by_id (404 not_found)
2020/04/10 01:07:47 ERROR : test.jpg: Failed to copy: failed to open source object: failed to open for download: bucket example_bucket does not have file: /b2api/v1/b2_download_file_by_id (404 not_found)
2020/04/10 01:07:47 ERROR : Attempt 2/3 failed with 1 errors and: failed to open source object: failed to open for download: bucket example_bucket does not have file: /b2api/v1/b2_download_file_by_id (404 not_found)
2020/04/10 01:07:47 ERROR : test.jpg: Failed to copy: failed to open source object: failed to open for download: bucket example_bucket does not have file: /b2api/v1/b2_download_file_by_id (404 not_found)
2020/04/10 01:07:47 ERROR : Attempt 3/3 failed with 1 errors and: failed to open source object: failed to open for download: bucket example_bucket does not have file: /b2api/v1/b2_download_file_by_id (404 not_found)
2020/04/10 01:07:47 Failed to copy: failed to open source object: failed to open for download: bucket example_bucket does not have file: /b2api/v1/b2_download_file_by_id (404 not_found)

rclone mount (moving file from remote to local directory):

mv: error reading 'test2.jpg': Input/output error

I am unable to post more than two links in a post given that I'm a new user, so I have pasted my various attempts to figure out the correct format for the download endpoint url in a pastebin:

https://pastebin.com/qiEvn3uZ

Hmm, I think this is probably a bug...

Try this

https://beta.rclone.org/branch/v1.51.0-155-g4209c768-b2-fix-download-url-beta/ (uploaded in 15-30 mins)

Thank you for looking into it! I'll try it ASAP.

Did you have a go with the above? Did it fix the problem?

I've merged this to master now which means it will be in the latest beta in 15-30 mins and released in v1.53