It is my understanding that this should Just Work™ automatically. You can only have one PRI per carrier, but different carrier PRIs will be loaded into separate slots. You don’t need to reupload an existing PRI when switching carriers. Doesn’t it work that way for you?
For example, I have this right now:
at!image?
TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
FW 1 GOOD 22 0 0 ?_? 02.23.00.00_?
FW 2 GOOD 21 0 0 ?_? 02.08.02.00_?
FW 3 GOOD 23 0 0 ?_? 02.24.03.00_?
FW 4 GOOD 17 0 0 ?_? 02.18.02.00_?
Max FW images: 4
Active FW image is at slot 3
TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
PRI FF GOOD 0 0 0 002.021_000 02.24.03.00_GENERIC
PRI FF GOOD 0 0 0 002.006_000 02.08.02.00_ORANGE-EU
Max PRI images: 50
OKYou’ll notice that the firmware image slots are numbered and can be addressed when uploading if you don’t want to trust the automatic slot selection. But the PRI slots are not numbered, and AFAIK there is no way to address a specifc slot when uploading PRIs. They are addressed by the carrier ID they apply to.