My builds don't modify bootloader at all, you keep the one that was installed last time with Android. When you see "Updating bootloader..." during update process it actually does nothing to bootloader, it's only about updating device tree.
I'm sorry about the boot issue. I have 3 S905(X) boxes, I made them automatically reboot every 30 seconds and all rebooted fine all the time with 7.0.3.011. It's hard for me to tell what's causing the issue when I cannot reproduce it.
for all the people using beelink minimx S905 1GB ram/1Gbit eth/8 GB rom and installed LE to internal NAND: I've tested three different bootloaders (u-boot) extacted from original Android FW (s905_103L1/s905_105L1/s905_107L1)
The best results for the (re)boot and powerdown issue comes with the bootloader from s905_105L1.
In attach the binary file.
In order to write the bootloader you need to boot successfully the box,
connect to the box via ssh and then flash the image.
First of all, copy bootloader.img to download (or update) shared folder on the box and then
ssh [email protected]<ip-addr-for-the-box>
dd if=downloads/bootloader.img of=/dev/bootloader