For second option you can simply use curl tool with the update API or tools on the target.
For example simply download the new update file with calling curl and after that install it with update tool or api. Works great for us!
See at:
legato.io/legato-docs/latest/too … pdate.html
legato.io/legato-docs/latest/too … pdate.html
legato.io/legato-docs/latest/leg … eMain.html
Cheers,
tom