I actually installed my uboot from the uboot-pinebookpro package, but, as said, it is rather worse than the default bootloader coming originally with the PBP. And it didn’t improve the sleep battery time.
OK, I came back to an acceptable state similar or equal to factory delivery, and documented all necessary steps at https://gitlab.com/EricPublic/miscericlaneous/-/blob/master/cheatsheets/pinebookpro.adoc?ref_type=heads#user-content-power-consumption
In a nutshell:
- download Tow-Boot pine64-pinebookPro-2022.07-006.tar.xz, unpack it and play
spi.installer.imgto SD-card according to PINE64 Pinebook Pro | Tow-Boot - get rid of u-boot according to Manjaro Forum
- install Tow-Boot using the SD-Card
- download Release Release 23.02 · manjaro-arm/pbpro-images · GitHub[Manjaro-ARM-minimal-pbpro-23.02.img and play it to SD-card
- use Tow-Boot (ESC!) to boot from the SD-Card.
- try the sleep mode (it continues to fail…), shutdown, reboot
- download Manjaro-ARM-kde-plasma-pbpro-bsp-23.01.img.gz (pre-release!), unpack it with unxz and play it to the eMMC with
dd if=Manjaro-ARM-kde-plasma-pbpro-bsp-23.01.img of=/dev/mmcblk2 oflag=direct,sync status=progress. - reboot and set-up Manjaro, then reboot.
- the first few reboots led to errors and a reboot-loop. This issue disappeared after a good night of sleep!?
- re-boot from the Tow-Boot SD card to wipe the SPI.
- situation is back to normal and sleep works again (but no improvements either).
And I got the information in the Pine64 forum that the consumption is normal and hardly to be improved. So, for me and for now, the Odyssey is over.