error "Invalid hash given"

[LeifSec]

running sudo rpi-update I get:

 *** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
 *** Performing self-update
 *** Relaunching after update
 *** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
FW_REV:
BOOTLOADER_REV:
 *** Invalid hash given

Running

• up to date Raspberian Stable (12) 32-.bit
• kernel: 6.12.34+rpt-rpi-v7
• github.com is resolved
• on raspberry 3B+

I have already reinstalled the kernel and raspi-update.

[pelwell]

Is your clock (date) reasonably accurate?

[LeifSec]

Yes, the clock is accurate (synchronized by chrony service).

P.S.:
I have also:

• Tried specific (latest) git git hashes (rpi-update hash).
• Tried different branches (rpi-update branch).
• Checked ca-certificates .

[LeifSec]

I have changed line 80 of /usr/bin/rpi-update.sh to

CURL_OPTIONS=${CURL_OPTIONS:-"-k"}

by adding the -koption so that curl is accepting non trusted ssl-certificates.

Then it works using the UPDATE_SELF=0 option.

(The certificate error has been causes by a Deep Inspection function of the external firewall.)

Following the error message Invalid hash given I have investigate kernel / bootloader versions etc. and I would have never thought about untrusted ssl-certificates. I have seen that other curl errors like in line 264 of rpi-updateare directly reported.