I use enigma2-plugin-extensions-openmultiboot_1.0+git132-20170103_all.ipk
What does it mean? Did you install by hand? No need for that, 'cause the OpenMultiboot (OMB) plugin is built-in in every images.
I have an error message
Which one? These kind of very generic messages help no one.
I had to initialize the disk
Which one? The internal HDD? And why? Did you use HDD as OMB device? If you don't explain...
I have reinstalled the Blackhole 3.10 image in flash
Which one was in flash before you reinstalled BH?
I don't know which image to install
And this is the most incredible question: do you think we can understand? What do you mean? Installing in flash? installing in OMB? installing here or there in order to have those in OMB working?
We are not there with you and we need as many details as possible.
And, finally, the procedure to install an image in OMB is:
1) take an image of your liking, keep the file zipped as you download from any website, but also (this is an important advice): RENAME IT AS SHORT AS POSSIBLE, like for instance, OBH5.zip, BH310.zip, and so on.
2) transfer to
/media/hdd/open-multiboot-upload
3) Install by the plugin's GUI in the image.