I can't download the Bootloader.Upgrade bootloader to 5.1.1
This will fix the all problems with the sound on my firmwares in the transition from the official 4.2.2 firmware.
Attention! I do not take any responsibility for possible negative consequences.
1) Make a backup copy of all data (including sections EFS, Modem, Preload)
2) Copy backup on PC
3) Download Odin 3.10 and Bootloader (This bootloader from P601XXUDOJ2 - official 5.1.1 service firmware).
4) Run device in "Download" mode.
5) Connect device to PC.
6) Run Odin
7) In the BL (bootloader) field, insert downloaded file BL_P601XXUDOJ2_CL5984967_QB6591366_REV00_user_low_ship.tar.md5
8) Сheck "F. Reset Time" Odin option. Must be selected.
9) Press "Start" button.... The bootloader will be installed and the device going to reboot.
10) You can go to TWRP and restore the backup (It is enough to restore the data and /data partition).
11) Install firmware and OpenGapps.
Currently, the firmware is installed on the following bootloader versions..
It says: "no mirrors found."