[Cpatel]

I’m planning on doing a femto unlock and using BM3 as the tuning platform.

I see two options on femtos website, bootmod3 custom rom OR bootmod3 regular unlock/no custom rom (picture attached).

I contacted protuning freaks and they said that with the custom rom option, I can use OTS maps.

Is there any reason why anyone would not choose the custom rom option if it includes the regular unlock and more?

I have a 2021 m340i. Comfirmed through the BM3 app that I need a femto unlock.

Also, on the fill form during checkout it asks for ECU and engine type. I’m assuming engine type is b58? What goes in the ECU field?

Thank you!

[gletonka]

there’s a very important reason why…

The Non custom ROM and Custom ROM unlocks can both run OTS tunes. If you do a non custom ROM unlock you will never be able to run a custom tune unless you send the DME back to be formatted for Custom ROM. The benefit to Custom ROM is that you will be able to run both OTS tunes and custom tunes, however you will only be able to use BM3. If you wanted to switch to MHD for example you would need to send your DME to be formatted for MHD custom ROM.

[Cpatel]

Originally Posted by gletonka

there’s a very important reason why…

The Non custom ROM and Custom ROM unlocks can both run OTS tunes. If you do a non custom ROM unlock you will never be able to run a custom tune unless you send the DME back to be formatted for Custom ROM. The benefit to Custom ROM is that you will be able to run both OTS tunes and custom tunes, however you will only be able to use BM3. If you wanted to switch to MHD for example you would need to send your DME to be formatted for MHD custom ROM.

Thank you so much for the clarification!
I only plan to ever use BM3 since that’s what I’ve used in my past bmws and it’s all I need. Cheers bro.

[GD1981]

Originally Posted by gletonka

there’s a very important reason why…

The Non custom ROM and Custom ROM unlocks can both run OTS tunes. If you do a non custom ROM unlock you will never be able to run a custom tune unless you send the DME back to be formatted for Custom ROM. The benefit to Custom ROM is that you will be able to run both OTS tunes and custom tunes, however you will only be able to use BM3. If you wanted to switch to MHD for example you would need to send your DME to be formatted for MHD custom ROM.

This isn’t true. I have a ‘21 and I was one of the first to unlock via femto and run bm3. I had a custom tune by F80 paul (93 map amd E30 map) as I was running a pure800 turbo, albeit on stock fuel system. Once customROM came out, I upgraded my fuel system and resent my DME back to Femto to load the customROM table/feature. for me, CustomROM was a breakthrough, since it enables users to run a flex tune, which I absolutely wanted when taking the next step in my build. A flex tune is a tune that adjusts based on ethanol content in your tank, and requires a flex fuel sensor to be installed - this sensor provides the input to bm3 and the tune adjusts based off this. CustomROM also allows for map switching from steering wheel controls, ability to read ethanol content from the dash (as long as you have the supporting hardware) and it also include the anti-lag feature.

So, yes, you can still get a custom tune with the base bm3 software, but you cant run a flex tune…two different things.

That said, there is no reason whatsoever two send out your DME and go with the base bm3 software. I dont even know why femto has that as an option, as there is no additional cost in adding customROM.