bootupctl update fails with "invalid unicode code point at line 108 column 40" on Fedora Silverblue 44

Environment

• OS: Fedora Silverblue 44 (x86_64)
• bootupd version: 0.2.33-1.fc44.x86_64
• rpm-ostree deployment: 44.20260524.0
• Boot method: EFI

Description

bootupctl update and bootupctl adopt-and-update both fail with:

error: Failed to update EFI: invalid unicode code point at line 108 column 40

The error occurs consistently on every boot via bootloader-update.service and also when run manually.

Steps to reproduce

sudo bootupctl update

Expected behavior

EFI bootloader update succeeds (grub2 from 2.12-56 to 2.12-58).

Actual behavior

Running as unit: bootupd.service
error: Failed to update EFI: invalid unicode code point at line 108 column 40

Investigation

• /var/lib/bootupd/ does not exist — bootupd was never successfully initialized
• EFI partition contains only standard ASCII filenames under /boot/efi/EFI/fedora/
• NVRAM had a corrupt Boot0001 entry (SHIM.EFI0000424f with trailing 42 4f bytes) — removed via efibootmgr -b 0001 -B, but error persists
• CSV files on EFI partition were UTF-16 LE encoded — converted to UTF-8, but error persists
• The error message ("line 108 column 40") appears to come from bootupd's internal JSON/serde parser, not from any user-visible file

Journal output

bootupctl[...]: error: Failed to update EFI: invalid unicode code point at line 108 column 40

Workaround applied

sudo systemctl mask bootloader-update.service

Start by reproducing bootupctl update and reviewing bootloader-update.service output, then trace the internal JSON/serde parsing associated with the reported line 108, column 40. Check /var/lib/bootupd/ and the EFI partition inputs while isolating the invalid Unicode source; done means EFI bootloader updates succeed without the parser error.