I can't access developer mode on my HP chromebook 11 g6 ee

I can’t access developer mode on my HP chromebook 11 g6 ee through a hard reset with esc+refresh+power after removing the battery (I wanted to disable secureboot to install coreboot). If I hold them Chromebook turns on and next Chromebook restarts instead of showing the recovery screen, displaying the normal logo as it does with every startup. I need to access shell in terminal and another things to install coreboot. What should I do?

Enable developer mode first before unplugging the battery.

Yes, I did that but still I have the same problem. I tried once again disconnect and connect the battery and then try hard reset but it don’t work.

If the Chromebook is enterprise enrolled, I could see that blocking things

It not seem to me. I bought chromebook and it already has had powerwash. I try discharge the battery to reset settings. Is there battery of BIOS or something to do to reset motherboard? If I try hard reset I recive only restart.

According to the docs, which I recommend everyone take a look at, it looks like the only caveat would be needing to unplug your battery to enable developer mode unless enrolled: Supported Devices and Platforms | Chrultrabook Docs
Further info here: Firmware Write Protect - MrChromebox Wiki
If you open up the Chromebook and the BIOS battery is replaceable, I also recommend replacing that if you’re having further issues.