Phone stuck on bootloop

Tried restoring/updating with iTunes and 3uTools with latest ios.

On 3uTools trying to "Fix Flash", it stops at 34%, on the "Updating NAND Firmware", after the phone shows the Apple logo and the update progress bar, then it hangs for a minute then reboot and returns to restore mode.

20:55:10.254:  Requesting SHSH
20:55:11.234:  Enter Recovery Mode
20:55:15.774:  Sending AppleLogo
20:55:15.803:  Sending Ramdisk
20:55:24.207:  Sending DeviceTree
20:55:24.222:  Sending RestoreSep
20:55:24.350:  Sending KernelCache << reboot to restore mode with the "Quick Flash"
20:55:32.333:  Restoring
20:55:34.497:  Sending RootTicket
20:55:34.501:  Waiting for NAND
20:55:34.514:  Updating NAND Firmware << reboot to restore mode with "Fix Flash" after 1 minute.

The battery was replaced 5-6 years ago, can this be battery related or a NAND failure?

Noticed that from uTools, if I launch a standard "Quick Flash" the phone reboot and goes back to restore mode after the "Sending KernelCache".

If I use the "Fix Flash" mode, it reaches the "Updating NAND Firmware" before going back into restore mode after 1 minute and no visible progress on the bar.