Resizing EFI partition fails

[PC-Dad]

Attempted to install an update to UEFI (8ACF version F24). Install failed stating "There is not enough free disk space..." which seems to be because the EFI partition, created at install, is 100 MB.

Following the instructions at https://h30434.www3.hp.com/t5/Desktop-Operating-Systems-and-Recovery/BIOS-Update-Error-Not-Enough-Di... and I can create a 300 MB EFI partition by shrinking the c: partition and bcdboot-ing an EFI onto that partition.

I can attempt to remove the old 100MB EFI partition, but on reboot it Partition Magician steps, which I didn't install, steps in and protects the 100 MB EFI partition and any further attempt to update the EFI fails.

Would appreciate any insight on how to address the Partition Magician and to use the new EFI partition.

[PC-Dad · Accepted solution]

Found answer partially in another post (thanks HP).

I needed to boot to BIOS Boot and select the new EFI partition and the boot file. This allowed me to be able to diskpart: delete partition override my old EFI partition and to run the firmware/BIOS update on the newly created 300 MB EFI partition.

Good learning experience. Thought it was related to Secure Boot or Partition Magic locking the EFI partition but no, just a BIOS Boot selection.