Hi again! While I was pointing out that I use a 4GB SDHC card, it reminded me of another issue I have on the TX1. I can set CHDK to boot on my 1GB SD card (from debug menu, followed by locking the card), but the same procedure fails on a 4GB SDHC card. On booting, it tells me that the card is locked (which didn't happen with the 1GB SD card), and CHDK isn't loaded.
I remember seeing a thread mentioning the "card locked" message, but I don't recall that it prevents the card from booting CHDK automatically.
Am I missing something? Thanks in advance!