Philips TV 39 PHS 4112/12 losing single channels or complete channel list.

[Greybeard]

Philips TV 39 PHS 4112/12 losing single channels (several times in the last months) or complete channel list (last night).
Old channel list could restored from last saved list on external USB thumb drive.
At the moment it's working again, but who knows for how long...?

I need help to identify the memory IC that stores the channel list.
Is there a service test to check the memory?

Service manual can be found here:
https://tel-spb.ru/tv/philips-39phs4112

[FF_CCSa1F]

Newer Philips TV chassis tend to store everything in a single flash chip, you can find it in section 7.2 of the service manual. They're also very known for data corruption both due to bad firmware programming and failing flash chips. What's worse is that Philips go out of their way to prevent reprogramming without data editing by putting serial number locks in the firmware.

When we've encountered Philips TVs acting up, we've usually factory reset them through the service menu, which usually gives fixes a bunch of intermittent issues, and then letting them run until they die. Some people online claim to be able to fix them, but we haven't had much luck. I really can't recommend Philips TVs from a repairability standpoint.

[Greybeard]

Thank you, then I'll try factory reset first.

I hoped the chip containing the channel list is a simple to replace 8 pin eeprom, but I could not find such in the schematics.
Definitely I will not try to replace a >40 pin ~0.5mm fine pitch TSOP (the "big" flash memory).

Do you think a firmware update would be an unnecessarily large risk?
Installed firmware version is 1.00, IIRC.

[FF_CCSa1F]

If you can find a firmware update, go for it. The fact that they rewrite a lot of the flash tends to do good, since it lets the wear levelling algorithm do its job. While it's not unheard of for Philips firmware updates to fail when the flash starts to go bad, if that happens it just means that the TV was barely hanging on by a thread to begin with.

[Greybeard]

The TV worked over a week without losing channels when I found a firmware update...

I could not resist and installed it as decribed.
I copied the 2 files to a USB thumbdrive and switched the TV on.
The message "upgrade in progress" and a green progress bar appeared on the screen for a few minutes.
When the progress bar reached the right end, the message "rebooting" appeared and the screen turned black immediately.
I waited several minutes, but the screen stayed black.
The update description said "don't switch off" and "don't touch the remote control". But what else could I do?
So I tried to switch the TV off (and on) using the remote control, but nоthing happened.
Now I tried to pull the AC plug and pushed it back again - again nothing happened.
I tried to turn on the TV using the remote control - nothing happened.
I tried to enter the service menu (code 123654) - nothing happened.

I think I brickеd the TV successfully. 

Does anybody know, how to rescue the device?