These devices can have one of two chips, and require a different baseband bbfw to be specified in futurerestore in order to work. However, it is easy to forget, and many people do not know this at all.
Could you add a check at the start of the process to check for the chip ID and abort the process before the restore begins, to avoid this happening? Similar to the check for matching AP nonce and for valid blobs.
Cross referencing the specified bbfw with the device baseband chip id should be enough for this, and all the baseband types are available here:
https://www.theiphonewiki.com/wiki/Firmware/iPhone/11.x
For example, iPhone 7 has (MDM9645) Qualcomm and (PMB9943) Intel depending on the variant, and they need different bbfw, but the restore only fails at the end, forcing an update to current firmware. Checking that the bbfw matches the device on 7, 8 and X could prevent this and save many people's jailbreaks.
This is the cause of many of the errorcode=-11 cases in the issues page and on reddit, because people have either forgotten, made a mistake, or didn't know about this.
This would be a great feature to make futurerestore more reliable and easier for the end user.
Thanks!