Yes, the Palma should be a piece of cake. It's using the SDM662, so we have a Firehose loader for it.
There's a recent update:
Code:
Model: Palma (English)
Finger: Onyx/Palma/Palma:11/2023-11-24_18-57_3.5_bf9002fb4b/43561:user/dev-keys
Link: http://firmware-us-volc.boox.com/85b1def9e1f86f3a3be143210cf1b322/update.upx
Size: 1,524,678,325
MD5: 85b1def9e1f86f3a3be143210cf1b322
And we are able to decrypt it with
decryptBooxUpdateUpx. The process is similar for all the Onyx.
@Chitter did a very nice write up
here (for a different model).