SL808x vs SL808xBTR profile usage

We have older procuct using the SL8084 and some newer product using the SL8084BTR. We are finding that the PDP profile for GPRS can be any value in the SL8084 but must be profile 1 in the SL8084BTR.
eg both have at
+CGDCONT?
+CGDCONT: 1,“IP”,“telstra.internet”,"",0,0
+CGDCONT: 2,“IP”,“telstra.internet”,"",0,0
and both respond with “OK” to the “at!SCACT=1,2” and have
at+CGACT?
+CGACT: 1,0
+CGACT: 2,1

at!SCACT?
!SCACT: 1,0
!SCACT: 2,1
but only the SL8084 has a network connection. The SL8084BTR does not.

Is this expected behaviour? Are there other configuration parameters that need to be set correctly for the Sl8084BTR to work with profile 2?

what is the ATI3 response for these two models respectively?
If i remember correctly, SL808XT is having OpenAT FW running on top of Qualcomm platform.

SL8084:
Manufacturer: Sierra Wireless, Incorporated
Model: SL8084
Revision: S3_0_0_1AP R1096 CNSZXD00000132 2011/09/22 21:06:44
IMEI: 356890040083432
IMEI SV: 5
FSN: CAF2492169610
3GPP Release 5
+GCAP: +CGSM,+DS,+ES

SL8084BTR:
Manufacturer: Sierra Wireless, Incorporated
Model: SL8084BTR
Revision: S4_1_0_21AP R2371 CNSHZ-ED-XP0031 2014/11/27 16:53:47
IMEI: 352266060587996
IMEI SV: 19
FSN: CHU0536335540
3GPP Release 5
+GCAP: +CGSM,+DS,+ES

As I understand it all ‘T’ suffixes have the OpenAT feature but we are not using it, just the basic modem functions.
Does the OpenAT firmware restrict the profile usage?

Maybeyou can try the same FW first

We are not in a position to do field upgrades of the modem firmware.
In any case, I want to know if there is meant to be a difference between them or if it just a matter of configuration.

if I remember correctly, the profile 2 data is routed to OAT FW.

Why don’t you just use the same FW as SL808x if it is working fine for you?

There are many hundreds of units in the field and we don’t have a way of updating the firmware in the modems.
Our workaround is to use profile 1 everywhere. I am just trying to establish why it is necessary. Your clue that “profile 2 is routed to the OAT FW” is great, it explains a lot. Sierra Wireless didn’t tell us about that when they started shipping us SL8084BTR instead of SL8084. We only found out that they differ recently when our firmware started trying to use profile 2.
Do you know of a document that explains the differences between SL808x and SL808xBTR ? A migration document for instance? I have searched Sierra Wireless web site but I couldn’t find anything.

Do you mean you want to downgrade all FW of SL8084BTR to S3_0_0_1AP so that you can use profile 2?

No. We have a work-around: Use profile 1 everywhere.
My concern was: Why do they differ in their behaviour? I think you’ve answered that: OpenAT
Now my concern is: What other differences are there that I don’t know about?
I’d like to find a Sierra Wireless migration document so I don’t get caught out again.

better do a “full” testing and see if now the modules using profile 1 is working fine for you.

You can see the two FW were 3 years apart, that can be a lot of changes.

I remember there were partition change, you cannot direct upgrade from S3_0_0_1 to S4_1_0_21

OK. At the time the SL8084 become obsolete and Sierra Wireless began shipping SL8084BTR instead, the implication was that no functionality changed. Indeed, in the years since we haven’t noticed anything different until now.
I just wonder what else is waiting to bite us. For example, an indication that profile 2 is reserved for OpenAT would have been good.

you mean for so many years, you did not use profile 2, but till now, you suddenly need to use profile 2 in the field?

Yes. That’s what happened. Our firmware (not the modem) had a configuration specifying profile 2 (a bug it should have specified 1), but early code didn’t use the item. A recent upgrade to our firmware, that started making use of this item, worked on some units and not on others. The fix is use 1 everywhere but I’m trying to work out what happened and if it can happen again.