RPi4B's got a PMIC replacement, so now there are Rev 1.5 variants with matching firmware requirements; more
Date: Mon, 04 Apr 2022 06:44:29 UTC
The 2022-Feb-08 https://forums.raspberrypi.com/viewtopic.php?t=329299 reports about v1.5 (via a "Moderator" "Engineer"): QUOTE The PMIC has been changed. Needs firmware from April 21 or later. . . . The bootloader has supported this since Apr 2021 (previous default release). END QUOTE I will note that, separately from this, the 2021-Nov-24 https://forums.raspberrypi.com/viewtopic.php?t=324653 reports about the stepping with the C0T labeling (via a "Moderator" "Engineer"): QUOTE Any current production of 8GB will be C0 anyway. . . . And just informationally, the C0 stepping fixed a bug in the accessible memory region for one of the peripherals, and improved some power gating on some HW blocks. The first means a driver no longer needs bounce buffers, and the second we save a tiny amount of power. END QUOTE Other sources report the EMMC2 bus addressing as no longer limited to 1 GB and the PCIe interface addressing as no longer limited to 3 GB. The following information is listed (in a different form) in https://github.com/raspberrypi/linux/issues/3210#issuecomment-680007995 : Old (B0T): emmc2bus dma-ranges ending in 40 00 00 00 New (C0T): emmc2bus dma-ranges ending in fc 00 00 00 (Not visible via a separate .dtb file: the device tree is dynamically adjusted to match the stepping before being handed over to later stages.) From what I've seen checking on the web and the like, it looks like the C0T stepping usage is not limited to the 8 GiByte RPi4B's (or even 8 and 4 GiByte): 2 GiByte examples are also reported as having been received. From what I saw, U-Boot had some 0xff800000UL instance with a matching size of 0x800000UL that was proposed as changed to 0xffc00000UL and 0x400000UL to avoid overlapping newly updated ARM/VideoCore firmware memory use. (I'm unsure if this is related to the wider addressing ranges reported above leading things to have been moved around.) The reference is from 2021-Jun-17: https://www.mail-archive.com/u-boot@lists.denx.de/msg409182.html I do not know the first U-Boot release to have a change for the type of issue. Overall I do not know the implications for FreeBSD's status. I only have access to older RPi4B's. === Mark Millard marklmi at yahoo.com