This instruction helps you to enable all LTE-features on your Qualcomm devices like 1024QAM DL and 256QAM UL. Some features only supported only with SDX52 and SDX55 modems.
Before continuing, I remind you these changes could end your device warranty. Be careful because this can make your device unusable.
Make sure your device have X55 Modem Baseband version HI2.0 or newer. In Android you can check this in Settings -> About -> Status and find Baseband version.
Qualcomm diag driver installed and access to QPST/EFS.
Hex File Editor (eg. HxD Editor).
This instruction is tested with OnePlus 8 (IN2013) and 8 Pro (IN2023). To access QPST with OnePlus 8, follow instructions here.
Open EFS Explorer and navigate to following folder: /nv/item_files/modem/lte/rrc/efs
In this folder, search for and backup lte_feature_disable and/or lte_feature_disable_Subscription01 to your computer and afterwards delete them from your phone EFS filesystem. If these files do not exist, find lte_feature_enable and/or lte_feature_enable_Subscription01 and copy these (or one if only one exists) files to your computer. Modify lte_feature_enable(_Subscription01) files as needed.
Then find lte_feature_enable and/or lte_feature_enable_Subscription01 and copy these one or both files to your computer. Modify these files.
For Qualcomm SDX52 and SDX55 modems, we have already modified files:
With all features enabled
Without 1024QAM DL enabled. This is recommended because most of networks do not have 1024QAM enabled.
Download it and replace current file with this file or modify it manually.
Change all values to 11111111 (FF) to enable all LTE-features what chipset support. Here is explanations of all Feature bits.
Copy file back to phone as ItemFile (don’t drag and drop).
Right click on EFS Explorer and select Copy Item File from PC.
Click Browse and find then file on your computer and then click OK. Wait the confirmation message of item transfer from EFS Explorer.
You can check enabled features in UE Capability Information message. To confirm you have 256QAM UL enabled, find “ul-256QAM-r14” in UE Capability Information message.