commit dae48ef41ef62fd0b416123995a6bc7eea4f3761
author LuK1337 <priv.luk@gmail.com> Mon Apr 06 14:38:58 2020 +0200
committer Anay Wadhera <anay1018@gmail.com> Fri Feb 26 18:49:59 2021 -0800
tree 95e1d4fa10110619b22c9e67f8c5928a5a142c55
parent 1d9764209f344005c5a6efeb069a0924c87b1fb5

fastboot: Bring back legacy A/B support

Some devices, such as the Essential PH-1, don't have an
updated bootloader and the bootloader is appending an extra
underscore.

This patch works around that issue by sanitizing the slot to be
inline with modern expectations.

Offending commit: https://github.com/aosp-mirror/platform_system_core/commit/42b18a518bac85c3eea14206f6cbafbd1e98a31f

Most of the commit above is not needed because an underscore + slot
is automatically appended when flashing to a partition. Normally, this
would result in something like boot__b instead of boot_b, where b is the
current slot.

Test: flash an image on mata without specifying slot, boots

Change-Id: Ia0b7cee603a4f9ba2e3a61ce6e369ca8c07a7caf

fastboot/fastboot.cpp

diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index f7edf8e..38be934 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -1103,6 +1103,7 @@
 static std::string get_current_slot() {
     std::string current_slot;
     if (fb->GetVar("current-slot", &current_slot) != fastboot::SUCCESS) return "";
+    if (current_slot[0] == '_') current_slot.erase(0, 1);
     return current_slot;
 }
 
@@ -1950,6 +1951,7 @@
             if (slot_override == "") {
                 std::string current_slot;
                 if (fb->GetVar("current-slot", &current_slot) == fastboot::SUCCESS) {
+                    if (current_slot[0] == '_') current_slot.erase(0, 1);
                     next_active = verify_slot(current_slot, false);
                 } else {
                     wants_set_active = false;