5.1 speakerphone bug - fixed by bootloader?

Since 5.1 lollipop, I've had the 'speakerphone bug' (cannot switch to/from speakerphone once call has been established) using stock Motorola roms. I have, however, read that the speakerphone works perfectly for some people using stock roms. I am guessing that my bootloader version is the problem (doesn't seem intuitive), and I would like to confirm that it works before I update my (old) bootloader. Can anyone conclusively confirm that the following environment works and does not have the 'speakerphone bug'?

• unlocked


• flash full ATT xt1058 5.1 rom from SBF except recovery.img


• rooted with supersu

For what it is worth, I tried the following combinations:
- ATT xt1058 5.1 from SBF with ATT 5.1 NON-HLOS.BIN + FSG.mbn = speakerphone bug (flashed everything except motoboot.img, gpt.bin and recovery.img)

- Brazilian xt1058 5.1 retail from proxuser's TWRP backup (/system and boot.img, thanks proxuser):

• with ATT 4.4.4 modem = speakerphone bug


• with ATT 5.1 modem (NON-HLOS.bin) from SBF = bootloop


• with ATT 5.1 modem (NON-HLOS.bin + FSG.mbn) from SBF = bootloop


• with Brazilian 5.1 modem (NON-HLOS.bin) from SBF = bootloop


• with Brazilian 5.1 modem (NON-HLOS.bin + FSG.mbn) from SBF = bootloop

- Brazilian xt1058 5.1 retail from update.zip made from SBF (/system and boot..img flashed with TWRP):

• with ATT 4.4.4 modem = speakerphone bug


• with ATT 5.1 modem (NON-HLOS.bin) from SBF = bootloop


• with ATT 5.1 modem (NON-HLOS.bin + FSG.mbn) from SBF = bootloop


• with Brazilian 5.1 modem (NON-HLOS.bin) from SBF = bootloop


• with Brazilian 5.1 modem (NON-HLOS.bin + FSG.mbn) from SBF = bootloop

- Brazilian xt1058 5.1 retail from SBF using fastboot = error when flashing system.img (sp space is not enough)

I always 'fastboot erase modemst1 and modemst2.
I always cleared cache and wiped dalvic.
I tried erasing all useradata at least once.


thanks!